#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using ull = unsigned long long;
int t, n, m;
string x, y;
int main() {
  cin >> t;
  while (t--) {
    cin >> x;
    cin >> y;
    n = (int)(x.length());
    m = (int)(y.length());
    reverse(x.begin(), x.end());
    reverse(y.begin(), y.end());
    int pos1 = 0;
    while (y[pos1] != '1') {
      ++pos1;
    }
    int pos2 = pos1;
    while (x[pos2] != '1') {
      ++pos2;
    }
    cout << pos2 - pos1 << endl;
  }
  return 0;
}
