#include <bits/stdc++.h>
using namespace std;
bool is_prime(long long n) {
  for (long long i = 2; i * i <= n; ++i) {
    if (n % i == 0) {
      return false;
    }
  }
  return true;
}
map<long long, long long> fact(long long n) {
  n = abs(n);
  map<long long, long long> ans;
  for (long long i = 2; i * i <= n; i++) {
    if (n % i == 0) {
      while (n % i == 0) {
        n /= i;
        ans[i]++;
      }
    }
  }
  if (n > 1) {
    ans[n]++;
  }
  return ans;
}
inline long long getPow(long long a, long long b) {
  long long res = 1ll, tp = a;
  while (b) {
    if (b & 1ll) {
      res *= tp;
    }
    tp *= tp;
    b >>= 1ll;
  }
  return res;
}
long long vec_mult(const pair<long long, long long>& t1,
                   const pair<long long, long long>& t2,
                   const pair<long long, long long>& t3) {
  const long long &x1 = t1.first, y1 = t1.second;
  const long long &x2 = t2.first, y2 = t2.second;
  const long long &x3 = t3.first, y3 = t3.second;
  return abs((x2 - x1) * (y3 - y1) - (y2 - y1) * (x3 - x1));
}
void ok() {
  cout << "YES" << endl;
  exit(0);
}
void no() {
  cout << "NO" << endl;
  exit(0);
}
inline long long nxt() {
  long long x;
  cin >> x;
  return x;
}
const long long N = 2e5 + 5, inf = 8e18, mod = 1000000007;
const double PI = 3.1415926536;
int days[13] = {0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(0), cout.tie(0);
  long long t = nxt();
  while (t--) {
    string s1, s2;
    cin >> s1 >> s2;
    reverse(s1.begin(), s1.end());
    reverse(s2.begin(), s2.end());
    bool f = 0;
    for (int i = 0; i < s2.size() && !f; i++) {
      if (s2[i] == '0') continue;
      for (int j = i; j < s1.size() && !f; j++) {
        if (s1[j] == '1') {
          cout << j - i << '\n';
          f = 1;
        }
      }
    }
    if (!f) {
      cout << "0\n";
    }
  }
  return 0;
}
