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 sys, os, io
  def rs(): return sys.stdin.readline().rstrip()
  def ri(): return int(sys.stdin.readline())
  def ria(): return list(map(int, sys.stdin.readline().split()))
  def ws(s): sys.stdout.write(s + '\n')
  def wi(n): sys.stdout.write(str(n) + '\n')
  def wia(a): sys.stdout.write(' '.join([str(x) for x in a]) + '\n')
  import math,datetime,functools,itertools,operator,bisect,fractions,statistics
  from collections import deque,defaultdict,OrderedDict,Counter
  from fractions import Fraction
  from decimal import Decimal
  from sys import stdout
  from heapq import heappush, heappop, heapify ,_heapify_max,_heappop_max,nsmallest,nlargest
  # sys.setrecursionlimit(111111) 
  INF=999999999999999999999999
  alphabets="abcdefghijklmnopqrstuvwxyz"
  class SortedList:
      def __init__(self, iterable=[], _load=200):
          """Initialize sorted list instance."""
          values = sorted(iterable)
          self._len = _len = len(values)
          self._load = _load
          self._lists = _lists = [values[i:i + _load] for i in range(0, _len, _load)]
          self._list_lens = [len(_list) for _list in _lists]
          self._mins = [_list[0] for _list in _lists]
          self._fen_tree = []
          self._rebuild = True
   
      def _fen_build(self):
          """Build a fenwick tree instance."""
          self._fen_tree[:] = self._list_lens
          _fen_tree = self._fen_tree
          for i in range(len(_fen_tree)):
              if i | i + 1 < len(_fen_tree):
                  _fen_tree[i | i + 1] += _fen_tree[i]
          self._rebuild = False
   
      def _fen_update(self, index, value):
          """Update `fen_tree[index] += value`."""
          if not self._rebuild:
              _fen_tree = self._fen_tree
              while index < len(_fen_tree):
                  _fen_tree[index] += value
                  index |= index + 1
   
      def _fen_query(self, end):
          """Return `sum(_fen_tree[:end])`."""
          if self._rebuild:
              self._fen_build()
   
          _fen_tree = self._fen_tree
          x = 0
          while end:
              x += _fen_tree[end - 1]
              end &= end - 1
          return x
   
      def _fen_findkth(self, k):
          """Return a pair of (the largest `idx` such that `sum(_fen_tree[:idx]) <= k`, `k - sum(_fen_tree[:idx])`)."""
          _list_lens = self._list_lens
          if k < _list_lens[0]:
              return 0, k
          if k >= self._len - _list_lens[-1]:
              return len(_list_lens) - 1, k + _list_lens[-1] - self._len
          if self._rebuild:
              self._fen_build()
   
          _fen_tree = self._fen_tree
          idx = -1
          for d in reversed(range(len(_fen_tree).bit_length())):
              right_idx = idx + (1 << d)
              if right_idx < len(_fen_tree) and k >= _fen_tree[right_idx]:
                  idx = right_idx
                  k -= _fen_tree[idx]
          return idx + 1, k
   
      def _delete(self, pos, idx):
          """Delete value at the given `(pos, idx)`."""
          _lists = self._lists
          _mins = self._mins
          _list_lens = self._list_lens
   
          self._len -= 1
          self._fen_update(pos, -1)
          del _lists[pos][idx]
          _list_lens[pos] -= 1
   
          if _list_lens[pos]:
              _mins[pos] = _lists[pos][0]
          else:
              del _lists[pos]
              del _list_lens[pos]
              del _mins[pos]
              self._rebuild = True
   
      def _loc_left(self, value):
          """Return an index pair that corresponds to the first position of `value` in the sorted list."""
          if not self._len:
              return 0, 0
   
          _lists = self._lists
          _mins = self._mins
   
          lo, pos = -1, len(_lists) - 1
          while lo + 1 < pos:
              mi = (lo + pos) >> 1
              if value <= _mins[mi]:
                  pos = mi
              else:
                  lo = mi
   
          if pos and value <= _lists[pos - 1][-1]:
              pos -= 1
   
          _list = _lists[pos]
          lo, idx = -1, len(_list)
          while lo + 1 < idx:
              mi = (lo + idx) >> 1
              if value <= _list[mi]:
                  idx = mi
              else:
                  lo = mi
   
          return pos, idx
   
      def _loc_right(self, value):
          """Return an index pair that corresponds to the last position of `value` in the sorted list."""
          if not self._len:
              return 0, 0
   
          _lists = self._lists
          _mins = self._mins
   
          pos, hi = 0, len(_lists)
          while pos + 1 < hi:
              mi = (pos + hi) >> 1
              if value < _mins[mi]:
                  hi = mi
              else:
                  pos = mi
   
          _list = _lists[pos]
          lo, idx = -1, len(_list)
          while lo + 1 < idx:
              mi = (lo + idx) >> 1
              if value < _list[mi]:
                  idx = mi
              else:
                  lo = mi
   
          return pos, idx
   
      def add(self, value):
          """Add `value` to sorted list."""
          _load = self._load
          _lists = self._lists
          _mins = self._mins
          _list_lens = self._list_lens
   
          self._len += 1
          if _lists:
              pos, idx = self._loc_right(value)
              self._fen_update(pos, 1)
              _list = _lists[pos]
              _list.insert(idx, value)
              _list_lens[pos] += 1
              _mins[pos] = _list[0]
              if _load + _load < len(_list):
                  _lists.insert(pos + 1, _list[_load:])
                  _list_lens.insert(pos + 1, len(_list) - _load)
                  _mins.insert(pos + 1, _list[_load])
                  _list_lens[pos] = _load
                  del _list[_load:]
                  self._rebuild = True
          else:
              _lists.append([value])
              _mins.append(value)
              _list_lens.append(1)
              self._rebuild = True
   
      def discard(self, value):
          """Remove `value` from sorted list if it is a member."""
          _lists = self._lists
          if _lists:
              pos, idx = self._loc_right(value)
              if idx and _lists[pos][idx - 1] == value:
                  self._delete(pos, idx - 1)
   
      def remove(self, value):
          """Remove `value` from sorted list; `value` must be a member."""
          _len = self._len
          self.discard(value)
          if _len == self._len:
              raise ValueError('{0!r} not in list'.format(value))
   
      def pop(self, index=-1):
          """Remove and return value at `index` in sorted list."""
          pos, idx = self._fen_findkth(self._len + index if index < 0 else index)
          value = self._lists[pos][idx]
          self._delete(pos, idx)
          return value
   
      def bisect_left(self, value):
          """Return the first index to insert `value` in the sorted list."""
          pos, idx = self._loc_left(value)
          return self._fen_query(pos) + idx
   
      def bisect_right(self, value):
          """Return the last index to insert `value` in the sorted list."""
          pos, idx = self._loc_right(value)
          return self._fen_query(pos) + idx
   
      def count(self, value):
          """Return number of occurrences of `value` in the sorted list."""
          return self.bisect_right(value) - self.bisect_left(value)
   
      def __len__(self):
          """Return the size of the sorted list."""
          return self._len
   
      def __getitem__(self, index):
          """Lookup value at `index` in sorted list."""
          pos, idx = self._fen_findkth(self._len + index if index < 0 else index)
          return self._lists[pos][idx]
   
      def __delitem__(self, index):
          """Remove value at `index` from sorted list."""
          pos, idx = self._fen_findkth(self._len + index if index < 0 else index)
          self._delete(pos, idx)
   
      def __contains__(self, value):
          """Return true if `value` is an element of the sorted list."""
          _lists = self._lists
          if _lists:
              pos, idx = self._loc_left(value)
              return idx < len(_lists[pos]) and _lists[pos][idx] == value
          return False
   
      def __iter__(self):
          """Return an iterator over the sorted list."""
          return (value for _list in self._lists for value in _list)
   
      def __reversed__(self):
          """Return a reverse iterator over the sorted list."""
          return (value for _list in reversed(self._lists) for value in reversed(_list))
   
      def __repr__(self):
          """Return string representation of sorted list."""
          return 'SortedList({0})'.format(list(self))
      
  class SegTree:
      
      def __init__(self, n):
          self.N = 1 << n.bit_length()
          self.tree = [0] * (self.N<<1)
      
      def update(self, i, j, v):
          i += self.N
          j += self.N
          while i <= j:
              if i%2==1: self.tree[i] += v
              if j%2==0: self.tree[j] += v
              i, j = (i+1) >> 1, (j-1) >> 1
      
      def query(self, i):
          v = 0
          i += self.N
          while i > 0:
              v += self.tree[i]
              i >>= 1
          return v
  
  def SieveOfEratosthenes(limit):
      """Returns all primes not greater than limit."""
      isPrime = [True]*(limit+1)
      isPrime[0] = isPrime[1] = False
      primes = []
      for i in range(2, limit+1):
          if not isPrime[i]:continue
          primes += [i]
          for j in range(i*i, limit+1, i):
              isPrime[j] = False
      return primes
  
  
  def main():
  
      mod=1000000007
      # InverseofNumber(mod)
      # InverseofFactorial(mod)
      # factorial(mod)
      starttime=datetime.datetime.now()
      if(os.path.exists('input.txt')):
          sys.stdin = open("input.txt","r")
          sys.stdout = open("output.txt","w")
                      
      tc = ri()
      
      for _ in range(tc):     
          n=ri()
          a=list(rs())
          b=list(rs())
          for i in range(n):
              if b[i]=='1':
                  if i-1>=0 and a[i-1]=='1':
                      a[i-1]='d'
                  
                  elif a[i]=='0':
                      a[i]='d'
                  elif i+1<n and a[i+1]=='1':
                      a[i+1]='d'
                      
          wi(Counter(a)['d'])
              
          
                              
         
         
          
          
          
                   
              
              
              
  
          
                                      
          
                  
                      
  
          
          
   
                  
          
          
          
          
          
          
  
                      
                  
                  
                  
          
          
          
              
          
                          
              
   
              
  
  
                  
  
          
          
          
          
          
         
          
         
  
          
          
  
              
              
              
                  
              
  
              
              
          
          
             
          
          
                   
                  
          
          
  
          
          
  
          
          
          
              
          
          
              
                  
  
              
              
                  
              
              
              
              
          
          
         
           
          
  
          
          
                      
                          
  
                      
             
                       
              
          
                  
          
          
              
          
          
          
          
          
  
      
          
          
          
                  
                  
          
          
          
      
  
          
          
          
  
          
                               
          
          
          
              
          
          
                       
          
          
                      
          
                       
                      
                      
                  
                  
                      
                  
          
          
              
                     
          
                      
  
          
          
                  
              
              
      
              
                          
          
      
  
          
      #<--Solving Area Ends
      endtime=datetime.datetime.now()
      time=(endtime-starttime).total_seconds()*1000
      if(os.path.exists('input.txt')):
          print("Time:",time,"ms")  
      
                  
  class FastReader(io.IOBase):
      newlines = 0
  
      def __init__(self, fd, chunk_size=1024 * 8):
          self._fd = fd
          self._chunk_size = chunk_size
          self.buffer = io.BytesIO()
  
      def read(self):
          while True:
              b = os.read(self._fd, max(os.fstat(self._fd).st_size, self._chunk_size))
              if not b:
                  break
              ptr = self.buffer.tell()
              self.buffer.seek(0, 2), self.buffer.write(b), self.buffer.seek(ptr)
          self.newlines = 0
          return self.buffer.read()
  
      def readline(self, size=-1):
          while self.newlines == 0:
              b = os.read(self._fd, max(os.fstat(self._fd).st_size, self._chunk_size if size == -1 else size))
              self.newlines = b.count(b"\n") + (not b)
              ptr = self.buffer.tell()
              self.buffer.seek(0, 2), self.buffer.write(b), self.buffer.seek(ptr)
          self.newlines -= 1
          return self.buffer.readline()
  
  
  class FastWriter(io.IOBase):
  
      def __init__(self, fd):
          self._fd = fd
          self.buffer = io.BytesIO()
          self.write = self.buffer.write
  
      def flush(self):
          os.write(self._fd, self.buffer.getvalue())
          self.buffer.truncate(0), self.buffer.seek(0)
  
  
  class FastStdin(io.IOBase):
      def __init__(self, fd=0):
          self.buffer = FastReader(fd)
          self.read = lambda: self.buffer.read().decode("ascii")
          self.readline = lambda: self.buffer.readline().decode("ascii")
  
  
  class FastStdout(io.IOBase):
      def __init__(self, fd=1):
          self.buffer = FastWriter(fd)
          self.write = lambda s: self.buffer.write(s.encode("ascii"))
          self.flush = self.buffer.flush
  
  
  if __name__ == '__main__':
      sys.stdin = FastStdin()
      sys.stdout = FastStdout()
      main()
      