#include <bits/stdc++.h>

#include <variant>

#define rep2(i, k, n) for (i64 i = (i64)(k); i < (i64)(n); i++)
#define rep(i, n) rep2(i, 0, n)
#define all(x) begin(x), end(x)
#ifdef ENV_LOCAL
#define dump \
  if (1) cerr
#else
#define dump \
  if (0) cerr
#endif

using namespace std;
using namespace std::string_literals;

using i32 = int32_t;
using i64 = int64_t;
using f64 = double;
using f80 = long double;
using vi32 = vector<i32>;
using vi64 = vector<i64>;

// using namespace harudake;

int main() {
  ios::sync_with_stdio(false);
  cin.tie(nullptr);
  i64 t;
  cin >> t;
  rep(ccnt, t) {
    string x, y;
    cin >> x >> y;
    if (x + y == y + x) {
      if (size(x) > size(y)) {
        cout << "X\n";
      } else {
        cout << "Y\n";
      }
    } else if (x + y > y + x) {
      cout << "X\n";
    } else {
      cout << "Y\n";
    }
  }

  return 0;
}