Untitled

#include <bits/stdc++.h>
using namespace std;

#define int long long

string convert_to_binary(int n) {
  string s = "";
  while (n > 0) {
    s += to_string(n % 2);
    n /= 2;
  }
  return s;
}

void solve() {
  int x, y;
  cin >> x >> y;
  string s1 = convert_to_binary(x);
  string s2 = convert_to_binary(y);
  int ans = 0;

  for (int i = 0; i < max(size(s1), size(s2)); i++) {
    if (s1[i] != s2[i]) {
      ans = pow(2,i);
      break;
    }
  }
  cout  << ans << endl;
  return;
}

signed main() {
  int t = 1;
  cin >> t;
  while (t--) {
    solve();
  }

  return 0;
}