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 sys
  import math
  import bisect
  from sys import stdin, stdout
  from math import gcd, floor, sqrt, log2, ceil
  from collections import defaultdict as dd
  from bisect import bisect_left as bl, bisect_right as br
  from bisect import insort
  from collections import Counter
  from collections import deque
  from heapq import heappush,heappop,heapify
  from itertools import permutations,combinations
  from itertools import accumulate as ac
  from random import randint as ri
  mod = int(1e9)+7
  mod = 998244353
   
  ip = lambda : int(stdin.readline())
  inp = lambda: map(int,stdin.readline().split())
  ips = lambda: stdin.readline().rstrip()
  out = lambda x : stdout.write(str(x)+"\n")
  
  
  t = ip()
  for _ in range(t):
      n = ip()
      a = ips()
      b = ips()
      dic = set()
      ans = 0
      for i in range(n):
          cur = set()
          cur.add(a[i])
          cur.add(b[i])
          if len(dic) == 0:
              if len(cur) == 2:
                  ans += 2
                  dic = set()
              else:
                  dic = set(list(dic)+list(cur))
          else:
              if len(cur) == 2:
                  ans += 2
                  if '0' in dic:
                      ans += 1
                  dic = set()
              else:
                  if '0' in cur and '0' in dic:
                      ans += 1
                  elif '0' in cur and '1' in dic:
                      ans += 2
                      dic = set()
                  elif '1' in cur and '0' in dic:
                      ans += 2
                      dic = set()
                  else:
                      pass
      if len(dic) != 0:
          if '0' in dic:
              ans += 1
  
      print(ans)
                      
          
          
                      
      
      
      
      
              
                  
          
              
      
      
              
  
              
  
              
              
  
              
  
              
              
              
  
      
      
  