description: A binary string is a string that consists of characters 0 and 1. A bi-table is a table that has exactly two rows of equal length, each being a binary string.
  
  Let \operatorname{MEX} of a bi-table be the smallest digit among 0, 1, or 2 that does not occur in the bi-table. For example, \operatorname{MEX} for \begin{bmatrix} 0011\\\ 1010 \end{bmatrix} is 2, because 0 and 1 occur in the bi-table at least once. \operatorname{MEX} for \begin{bmatrix} 111\\\ 111 \end{bmatrix} is 0, because 0 and 2 do not occur in the bi-table, and 0 < 2.
  
  You are given a bi-table with n columns. You should cut it into any number of bi-tables (each consisting of consecutive columns) so that each column is in exactly one bi-table. It is possible to cut the bi-table into a single bi-table — the whole bi-table.
  
  What is the maximal sum of \operatorname{MEX} of all resulting bi-tables can be?
  
  Input
  
  The input consists of multiple test cases. The first line contains a single integer t (1 ≤ t ≤ 10^4) — the number of test cases. Description of the test cases follows.
  
  The first line of the description of each test case contains a single integer n (1 ≤ n ≤ 10^5) — the number of columns in the bi-table.
  
  Each of the next two lines contains a binary string of length n — the rows of the bi-table.
  
  It's guaranteed that the sum of n over all test cases does not exceed 10^5.
  
  Output
  
  For each test case print a single integer — the maximal sum of \operatorname{MEX} of all bi-tables that it is possible to get by cutting the given bi-table optimally.
  
  Example
  
  Input
  
  
  4
  7
  0101000
  1101100
  5
  01100
  10101
  2
  01
  01
  6
  000000
  111111
  
  
  Output
  
  
  8
  8
  2
  12
  
  Note
  
  In the first test case you can cut the bi-table as follows:
  
    * \begin{bmatrix} 0\\\ 1 \end{bmatrix}, its \operatorname{MEX} is 2.
    * \begin{bmatrix} 10\\\ 10 \end{bmatrix}, its \operatorname{MEX} is 2.
    * \begin{bmatrix} 1\\\ 1 \end{bmatrix}, its \operatorname{MEX} is 0.
    * \begin{bmatrix} 0\\\ 1 \end{bmatrix}, its \operatorname{MEX} is 2.
    * \begin{bmatrix} 0\\\ 0 \end{bmatrix}, its \operatorname{MEX} is 1.
    * \begin{bmatrix} 0\\\ 0 \end{bmatrix}, its \operatorname{MEX} is 1.
  
  
  
  The sum of \operatorname{MEX} is 8.
solution: import java.io.*;
  import java.lang.reflect.Array;
  import java.util.*;
  
  public class Main {
      // final CustomReader in = new CustomReader("input.txt");
      final CustomReader in = new CustomReader();
      final PrintWriter out = new PrintWriter(System.out);
  
      void solve() {
          int t = in.nextInt();
          while (t-- > 0) {
              int n = in.nextInt();
              String upS = in.nextLine();
              String downS = in.nextLine();
  
              boolean findZero = false;
              int answer = 0;
              for (int i = 0; i < n; i++) {
                  int up = upS.charAt(i) - '0';
                  int down = downS.charAt(i) - '0';
  
                  if (up + down == 2) {
                      findZero = true;
                  } else if (up + down == 1) {
                      answer += 2;
                      findZero = false;
                  } else {
                      if (findZero) {
                          answer += 2;
                          findZero = false;
                      } else if (i + 1 < n) {
                          int nextUp = upS.charAt(i+1) - '0';
                          int nextDown = downS.charAt(i+1) - '0';
                          if (nextDown + nextUp == 2) {
                              answer += 2;
                              i++;
                          } else {
                              answer += 1;
                          }
                      } else {
                          answer += 1;
                      }
  
                  }
              }
              out.println(answer);
          }
      }
  
      public static void main(String[] args) { Main s = new Main(); s.solve(); s.out.close(); }
  
      private static class CustomReader {
          private final InputStream stream;
          private final byte[] buf = new byte[8192];
          private int curChar;
          private int numChars;
  
          CustomReader() {
              stream = System.in;
          }
  
          CustomReader(String fileName) {
              InputStream temp = null;
              try {
                  temp = new FileInputStream(fileName);
              } catch (FileNotFoundException e) {
                  e.printStackTrace();
              }
              stream = temp;
          }
  
          String nextLine() {
              int c = read();
              StringBuilder res = new StringBuilder();
              while (!isEndOfLine(c)) {
                  res.appendCodePoint(c);
                  c = read();
              }
              if (c == '\r') read();
              return res.toString();
          }
  
          String nextString() {
              int c = read();
              while (isSpaceChar(c)) c = read();
              StringBuilder res = new StringBuilder();
              while (!isSpaceChar(c)) {
                  res.appendCodePoint(c);
                  c = read();
              }
              if (c == '\r') read();
              return res.toString();
          }
  
          long nextLong() {
              int c = read();
              while (isSpaceChar(c)) c = read();
              int sgn = 1;
              if (c == '-') {
                  sgn = -1;
                  c = read();
              }
              long res = 0;
              while (!isSpaceChar(c)) {
                  if (c < '0' || c > '9') throw new InputMismatchException();
                  res *= 10;
                  res += c - '0';
                  c = read();
              }
              if (c == '\r') read();
              return res * sgn;
          }
  
          int nextInt() {
              int c = read();
              while (isSpaceChar(c)) c = read();
              int sgn = 1;
              if (c == '-') {
                  sgn = -1;
                  c = read();
              }
              int res = 0;
              while (!isSpaceChar(c)) {
                  if (c < '0' || c > '9') throw new InputMismatchException();
                  res *= 10;
                  res += c - '0';
                  c = read();
              }
              if (c == '\r') read();
              return res * sgn;
          }
  
          int[] nextArray(int n) {
              int[] arr = new int[n];
              for (int i = 0; i < n; i++) arr[i] = nextInt();
              return arr;
          }
  
          double nextDouble() {
              return Double.parseDouble(nextString());
          }
  
          boolean hasNext() {
              if (numChars == -1) return false;
              return curChar < numChars || curChar == buf.length || numChars == 0; // Probably
          }
  
          private int read() {
              if (numChars == -1) throw new InputMismatchException();
              if (curChar >= numChars) {
                  curChar = 0;
                  try {
                      numChars = stream.read(buf);
                  } catch (IOException e) {
                      throw new InputMismatchException();
                  }
                  if (numChars <= 0) return -1;
              }
              return buf[curChar++];
          }
  
          private static boolean isSpaceChar(int c) {
              return c == ' ' || c == '\n' || c == '\r' || c == '\t' || c == -1;
          }
  
          private static boolean isEndOfLine(int c) {
              return c == '\n' || c == '\r' || c == -1;
          }
      }
  }
  