#include <bits/stdc++.h>
#include <atcoder/all>
using namespace std;
using namespace atcoder;
using mint = modint998244353;
using ll = long long;
#define all(x) x.begin(), x.end()
#define rep(i, n) for (int i = 0; i < n; i++)

void solve(void){
    string x, y;
    cin >> x >> y;
    if(x + y > y + x){
        cout << 'X' << endl;
    }
    else if(x + y < y + x){
        cout << 'Y' << endl;
    }
    else if(x.length() > y.length()){
        cout << 'X' << endl;
    }
    else cout << 'Y' << endl;
}
int main(void)
{
    int t;
    cin >> t;
    rep(i, t){
        solve();
    }
    return 0;
}