#include <iostream>
#include <vector>
#include <cmath>
#include <map>
#include <set>
#include <iomanip>
#include <queue>
#include <algorithm>
#include <numeric>
#include <deque>
#include <complex>
#include <cassert>

using namespace std;
using ll = long long;

int main(){

    int T;
    cin >> T;

    while(T){
        T--;
        string x, y, s, t;
        cin >> x >> y;
        s = x+y; t = y+x;
        if (s > t) cout << "X" << endl;
        else if (s == t) cout << (x.size() > y.size() ? "X" : "Y") << endl;
        else cout << "Y" << endl;
    }

    return 0;
}