#include <bits/stdc++.h>
using namespace std;
inline int in() {
  int x;
  scanf("%d", &x);
  return x;
}
bool Check(int N, int pos) { return (bool)(N & (1 << pos)); }
int Set(int N, int pos) { return N = N | (1 << pos); }
int fx[] = {+0, +0, +1, -1, -1, +1, -1, +1};
int fy[] = {-1, +1, +0, +0, +1, +1, -1, -1};
int hr[] = {-2, -2, -1, +1, +2, +2, -1, +1};
int hc[] = {+1, -1, +2, +2, -1, +1, -2, -2};
int dx[] = {+1, -1, +0, +0};
int dy[] = {+0, +0, +1, -1};
const int MAXN = (int)1e5 + 9;
int main() {
  int i, j, k, l, m, n, p, q, x, y, u, v, r, tc, t;
  cin >> tc;
  while (tc--) {
    string s1, s2;
    cin >> s1 >> s2;
    reverse(s1.begin(), s1.end());
    reverse(s2.begin(), s2.end());
    i = 0;
    while (s2[i] == '0') i++;
    j = i;
    while (s1[j] == '0') j++;
    cout << j - i << endl;
  }
  return 0;
}
