description: There is a chessboard of size n by n. The square in the i-th row from top and j-th column from the left is labelled (i,j).
  
  Currently, Gregor has some pawns in the n-th row. There are also enemy pawns in the 1-st row. On one turn, Gregor moves one of his pawns. A pawn can move one square up (from (i,j) to (i-1,j)) if there is no pawn in the destination square. Additionally, a pawn can move one square diagonally up (from (i,j) to either (i-1,j-1) or (i-1,j+1)) if and only if there is an enemy pawn in that square. The enemy pawn is also removed.
  
  Gregor wants to know what is the maximum number of his pawns that can reach row 1?
  
  Note that only Gregor takes turns in this game, and the enemy pawns never move. Also, when Gregor's pawn reaches row 1, it is stuck and cannot make any further moves.
  
  Input
  
  The first line of the input contains one integer t (1≤ t≤ 2⋅ 10^4) — the number of test cases. Then t test cases follow.
  
  Each test case consists of three lines. The first line contains a single integer n (2≤ n≤ 2⋅{10}^{5}) — the size of the chessboard.
  
  The second line consists of a string of binary digits of length n, where a 1 in the i-th position corresponds to an enemy pawn in the i-th cell from the left, and 0 corresponds to an empty cell.
  
  The third line consists of a string of binary digits of length n, where a 1 in the i-th position corresponds to a Gregor's pawn in the i-th cell from the left, and 0 corresponds to an empty cell.
  
  It is guaranteed that the sum of n across all test cases is less than 2⋅{10}^{5}.
  
  Output
  
  For each test case, print one integer: the maximum number of Gregor's pawns which can reach the 1-st row.
  
  Example
  
  Input
  
  
  4
  3
  000
  111
  4
  1111
  1111
  3
  010
  010
  5
  11001
  00000
  
  
  Output
  
  
  3
  4
  0
  0
  
  Note
  
  In the first example, Gregor can simply advance all 3 of his pawns forward. Thus, the answer is 3.
  
  In the second example, Gregor can guarantee that all 4 of his pawns reach the enemy row, by following the colored paths as demonstrated in the diagram below. Remember, only Gregor takes turns in this "game"!
  
  <image>
  
  In the third example, Gregor's only pawn is stuck behind the enemy pawn, and cannot reach the end.
  
  In the fourth example, Gregor has no pawns, so the answer is clearly 0.
solution: import java.io.*;
  import java.util.*;
  import java.lang.*;
  
  public class codeforces {
      public static void main(String[] args) {
          InputStream inputStream = System.in;
          OutputStream outputStream = System.out;
          if (System.getProperty("ONLINE_JUDGE") == null) {
              long startTime = System.currentTimeMillis();
              try {
                  sc = new InputReader(new FileInputStream("input.txt"));
                  out = new PrintWriter(new FileOutputStream("output.txt"));
                  pr = new PrintWriter(new FileOutputStream("error.txt"));
              } catch (Exception ignored) {
              }
              int t = 1;
              int tt = t;
              t = sc.nextInt();
              while (t-- > 0) {
                  solve();
              }
              long endTime = System.currentTimeMillis();
              System.out.println("Time: " + (endTime - startTime) / tt + " ms");
              out.flush();
              pr.flush();
  
          } else {
              sc = new InputReader(inputStream);
              out = new PrintWriter(outputStream);
              pr = new PrintWriter(outputStream);
              int t = 1;
              t = sc.nextInt();
              while (t-- > 0) {
                  solve();
              }
              out.flush();
          }
      }
  
      public static void solve() {
          int n = sc.nextInt();
          char[] s1 = sc.next().toCharArray();
          int count = 0;
          char[] s2 = sc.next().toCharArray();
          for (int i = 0; i < n; i++) {
              if (s2[i] == '1') {
                  if (s1[i] == '0')
                      count++;
                  else if (i != 0 && '1' == s1[i - 1]) {
                      s1[i - 1] = '0';
                      count++;
                  } else if (i != n - 1 && s1[i + 1] == '1') {
                      s1[i + 1] = '0';
                      count++;
                  }
              }
          }
          out.println(count);
      }
  
      /*******************************************************************/
      /*
       * Set Iterator Iterator value = set.iteratoputr(); Displaying the values after
       * iterating through the iterator
       * System.out.println("The iterator values are: "); while (value.hasNext()) {
       * System.out.println(value.next()); }
       */
  
      // Map Iterator:
      // for (Map.Entry<Integer, Integer> entry : map.entrySet()){}
  
      // pair sort
      // Arrays.sort(lap, new Comparator<Pair>() {
      // @Override
      // public int compare(Pair p1, Pair p2) {
      // return Integer.compare(p1.first, p2.first);
  
      // }
      // });
  
      // Globals
  
      public static int inf = Integer.MAX_VALUE;
      public static int minf = Integer.MIN_VALUE;
      public static int mod = 1000000007;
      public static int ml = (int) 1e9;
      public static InputReader sc;
      public static PrintWriter out;
      public static PrintWriter pr;
  
      // Pair
  
      static class Pair {
          int first, second;
  
          Pair(int x, int y) {
              this.first = x;
              this.second = y;
          }
      }
  
      // FastReader Class
  
      static class InputReader {
          public BufferedReader reader;
          public StringTokenizer tokenizer;
  
          public InputReader(InputStream stream) {
              reader = new BufferedReader(new InputStreamReader(stream), 32768);
              tokenizer = null;
          }
  
          public String next() {
              while (tokenizer == null || !tokenizer.hasMoreTokens()) {
                  try {
                      tokenizer = new StringTokenizer(reader.readLine());
                  } catch (IOException e) {
                      throw new RuntimeException(e);
                  }
              }
              return tokenizer.nextToken();
          }
  
          public int nextInt() {
              return Integer.parseInt(next());
          }
  
          public long nextLong() {
              return Long.parseLong(next());
          }
  
          public double nextDouble() {
              return Double.parseDouble(next());
          }
      }
  
      // Node class
  
      static class Node {
          Node next;
          int data;
  
          Node(int x) {
              next = null;
              this.data = x;
          }
      }
  
      // Req Functions
  
      public static int gcd(int a, int b) {
          if (a == 0)
              return b;
          return gcd(b % a, a);
      }
  
      public static int lcm(int a, int b) {
          return (a / gcd(a, b)) * b;
      }
  
      public static long gcd(long a, long b) {
          if (a == 0)
              return b;
          return gcd(b % a, a);
      }
  
      public static long lcm(long a, long b) {
          return (a / gcd(a, b)) * b;
      }
  
      static long nCr(int n, int r) {
          return fact(n) / (fact(r) * fact(n - r));
      }
  
      static long fact(int n) {
          int res = 1;
          for (int i = 2; i <= n; i++)
              res = res * i;
          return res;
      }
  
      static long nCr(long n, long r) {
          return fact(n) / (fact(r) * fact(n - r));
      }
  
      static long fact(long n) {
          int res = 1;
          for (int i = 2; i <= n; i++)
              res = res * i;
          return res;
      }
  
      public static String reverseString(String input) {
          StringBuilder str = new StringBuilder("");
  
          for (int i = input.length() - 1; i >= 0; i--) {
              str.append(input.charAt(i));
          }
          return str.toString();
      }
  
      public static int maxOf3(int x, int y, int z) {
          return Math.max(x, Math.max(y, z));
      }
  
      public static int minof3(int x, int y, int z) {
          return Math.min(x, Math.min(y, z));
      }
  
      public static long maxOf3(long x, long y, long z) {
          return Math.max(x, Math.max(y, z));
      }
  
      public static long minof3(long x, long y, long z) {
          return Math.min(x, Math.min(y, z));
      }
  
      public static void arrInput(int[] arr, int n) {
          for (int i = 0; i < n; i++)
              arr[i] = sc.nextInt();
      }
  
      public static void arrInput(long[] arr, int n) {
          for (int i = 0; i < n; i++)
              arr[i] = sc.nextLong();
      }
  
      public static void arrInput(Pair[] pair, int n) {
          for (int i = 0; i < n; i++)
              pair[i] = new Pair(sc.nextInt(), sc.nextInt());
      }
  
      public static int lowerBound(int[] arr, int x) {
          int l = -1, r = arr.length;
          while (l + 1 < r) {
              int m = (l + r) >>> 1;
              if (arr[m] >= x)
                  r = m;
              else
                  l = m;
          }
          return r;
      }
  
      public static int upperBound(int[] arr, int x) {
          int l = -1, r = arr.length;
          while (l + 1 < r) {
              int m = (l + r) >>> 1;
              if (arr[m] <= x)
                  l = m;
              else
                  r = m;
          }
          return l + 1;
      }
  
      public static void fill(char[][] arr, char c) {
          int n = arr.length, m = arr[0].length;
          for (int i = 0; i < n; i++)
              for (int j = 0; j < m; j++)
                  arr[i][j] = c;
      }
  
      public static void fill(int[][] arr, int c) {
          int n = arr.length, m = arr[0].length;
          for (int i = 0; i < n; i++)
              for (int j = 0; j < m; j++)
                  arr[i][j] = c;
      }
  
      public static void fill(long[][] arr, long c) {
          int n = arr.length, m = arr[0].length;
          for (int i = 0; i < n; i++)
              for (int j = 0; j < m; j++)
                  arr[i][j] = c;
      }
  
      public static void merge(int arr[], int l, int m, int r) {
          int n1 = m - l + 1;
          int n2 = r - m;
          int L[] = new int[n1];
          int R[] = new int[n2];
          for (int i = 0; i < n1; ++i)
              L[i] = arr[l + i];
          for (int j = 0; j < n2; ++j)
              R[j] = arr[m + 1 + j];
          int i = 0, j = 0;
          int k = l;
          while (i < n1 && j < n2) {
              if (L[i] >= R[j]) {
                  arr[k] = L[i];
                  i++;
              } else {
                  arr[k] = R[j];
                  j++;
              }
              k++;
          }
          while (i < n1) {
              arr[k] = L[i];
              i++;
              k++;
          }
          while (j < n2) {
              arr[k] = R[j];
              j++;
              k++;
          }
      }
  
      public static void reversesort(int arr[], int l, int r) {
          if (l < r) {
              int m = l + (r - l) / 2;
              reversesort(arr, l, m);
              reversesort(arr, m + 1, r);
              merge(arr, l, m, r);
          }
      }
  
      public static void merge(long arr[], int l, int m, int r) {
          int n1 = m - l + 1;
          int n2 = r - m;
          long L[] = new long[n1];
          long R[] = new long[n2];
          for (int i = 0; i < n1; ++i)
              L[i] = arr[l + i];
          for (int j = 0; j < n2; ++j)
              R[j] = arr[m + 1 + j];
          int i = 0, j = 0;
          int k = l;
          while (i < n1 && j < n2) {
              if (L[i] >= R[j]) {
                  arr[k] = L[i];
                  i++;
              } else {
                  arr[k] = R[j];
                  j++;
              }
              k++;
          }
          while (i < n1) {
              arr[k] = L[i];
              i++;
              k++;
          }
          while (j < n2) {
              arr[k] = R[j];
              j++;
              k++;
          }
      }
  
      public static void reversesort(long arr[], int l, int r) {
          if (l < r) {
              int m = l + (r - l) / 2;
              reversesort(arr, l, m);
              reversesort(arr, m + 1, r);
              merge(arr, l, m, r);
          }
      }
  
      public static void sort(int[] arr) {
          Arrays.sort(arr);
      }
  
      public static void sort(long[] arr) {
          Arrays.sort(arr);
      }
  
      public static void sort(ArrayList<Integer> list) {
          Collections.sort(list);
      }
  
      public static long sumint(int n) {
          long ans = 0;
          char[] s = String.valueOf(n).toCharArray();
          for (int i = 0; i < s.length; ++i)
              ans += s[i] - '0';
          return ans;
      }
  
      public static long sumint(long n) {
          long ans = 0;
          char[] s = String.valueOf(n).toCharArray();
          for (int i = 0; i < s.length; ++i)
              ans += s[i] - '0';
          return ans;
      }
  
      // debug
  
      public static void debug() {
          if (sysFlag)
              pr.println("");
      }
  
      public static boolean sysFlag = System.getProperty("ONLINE_JUDGE") == null;
  
      public static void debug(int[][] dp) {
          if (sysFlag) {
              for (int i = 0; i < dp.length; ++i) {
                  pr.print(i + "--> ");
                  for (int j = 0; j < dp[0].length; ++j) {
                      pr.print(dp[i][j] + " ");
                  }
                  pr.println("");
              }
          }
      }
  
      public static void debug(char[][] arr) {
          if (sysFlag) {
              for (int i = 0; i < arr.length; ++i) {
                  for (int j = 0; j < arr[0].length; ++j) {
                      pr.print(arr[i][j]);
                  }
                  pr.println("");
              }
          }
      }
  
      public static void debug(long[][] dp) {
          if (sysFlag) {
              for (int i = 0; i < dp.length; ++i) {
                  pr.print(i + "--> ");
                  for (int j = 0; j < dp[0].length; ++j) {
                      pr.print(dp[i][j] + " ");
                  }
                  pr.println("");
              }
          }
      }
  
      public static void debug(int x) {
          if (sysFlag)
              pr.println("Int-Ele: " + x);
      }
  
      public static void debug(String x) {
          if (sysFlag)
              pr.println("String: " + x);
      }
  
      public static void debug(char x) {
          if (sysFlag)
              pr.println("Char: " + x);
      }
  
      public static void debug(long x) {
          if (sysFlag)
              pr.println("Long-Ele: " + x);
      }
  
      public static void debug(int[] arr) {
          if (sysFlag) {
              for (int i = 0; i < arr.length; ++i) {
                  pr.println(i + " -> " + arr[i]);
              }
          }
      }
  
      public static void debug(char[] arr) {
          if (sysFlag) {
              for (int i = 0; i < arr.length; ++i) {
                  pr.println(i + " -> " + arr[i]);
              }
          }
      }
  
      public static void debug(long[] arr) {
          if (sysFlag) {
              for (int i = 0; i < arr.length; ++i) {
                  pr.println(i + " -> " + arr[i]);
              }
          }
      }
  
      public static void debug(ArrayList<Integer> list) {
          if (sysFlag) {
              for (int i = 0; i < list.size(); ++i) {
                  pr.println(i + " -> " + list.get(i));
              }
          }
      }
  
      public static void Ldebug(ArrayList<Long> list) {
          if (sysFlag) {
              for (int i = 0; i < list.size(); ++i) {
                  pr.println(i + " -> " + list.get(i));
              }
          }
      }
  
      public static void debugmapII(HashMap<Integer, Integer> map) {
          if (sysFlag) {
              for (Map.Entry<Integer, Integer> entry : map.entrySet())
                  pr.println("Key => " + entry.getKey() + ", Value => " + entry.getValue());
          }
      }
  
      public static void debugmapLI(HashMap<Long, Integer> map) {
          if (sysFlag) {
              for (Map.Entry<Long, Integer> entry : map.entrySet())
                  pr.println("Key => " + entry.getKey() + ", Value => " + entry.getValue());
          }
      }
  
      public static void debugmapLL(HashMap<Long, Long> map) {
          if (sysFlag) {
              for (Map.Entry<Long, Long> entry : map.entrySet())
                  pr.println("Key => " + entry.getKey() + ", Value => " + entry.getValue());
          }
      }
  
      public static void debugmapIL(HashMap<Integer, Long> map) {
          if (sysFlag) {
              for (Map.Entry<Integer, Long> entry : map.entrySet())
                  pr.println("Key => " + entry.getKey() + ", Value => " + entry.getValue());
          }
      }
  
      public static void debugmapSL(HashMap<String, Long> map) {
          if (sysFlag) {
              for (Map.Entry<String, Long> entry : map.entrySet())
                  pr.println("Key => " + entry.getKey() + ", Value => " + entry.getValue());
          }
      }
  
      public static void debugmapCL(HashMap<Character, Long> map) {
          if (sysFlag) {
              for (Map.Entry<Character, Long> entry : map.entrySet())
                  pr.println("Key => " + entry.getKey() + ", Value => " + entry.getValue());
          }
      }
  
      public static void debugmapSI(HashMap<String, Integer> map) {
          if (sysFlag) {
              for (Map.Entry<String, Integer> entry : map.entrySet())
                  pr.println("Key => " + entry.getKey() + ", Value => " + entry.getValue());
          }
      }
  
      public static void debugmapCI(HashMap<Character, Integer> map) {
          if (sysFlag) {
              for (Map.Entry<Character, Integer> entry : map.entrySet())
                  pr.println("Key => " + entry.getKey() + ", Value => " + entry.getValue());
          }
      }
  
      public static void debug(Set<Integer> set) {
          if (sysFlag) {
              Iterator value = set.iterator();
              int i = 1;
              while (value.hasNext()) {
                  pr.println((i++) + "-> " + value.next());
              }
          }
      }
  
      public static void debug(Pair[] pair, int n) {
          if (sysFlag) {
              for (int i = 0; i < n; i++) {
                  pr.println("first:" + pair[i].first + " second:" + pair[i].second);
              }
          }
      }
  }
  