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

using ll = long long;
using ull = unsigned long long;
using ld = long double;
template<class t> using vc = vector<t>;
template<class t> using vvc = vc<vc<t>>;
using pi = pair<int,int>;
using vi = vc<int>;
using vvi = vvc<int>;

#define rep(i,a,b) for (int i = a; i < b; i++)
#define irep(i,a,b) for (int i = a; i > b; i--)
#define print(n) cout << n << endl
#define rup(a,b) (a+b-1)/b

void solve(){
    string x,y;cin>>x>>y;
    if(x+y<y+x) print("X");
    else if (x+y>y+x) print("Y");
    else{
        if(x.size()>y.size()) print("X");
        else print("Y");
    }
    return;
}

int main(){
    cout << fixed << setprecision(15);
    
    int T;
    cin >> T;
    rep(i,0,T) solve();
    
    //system("pause");
    return 0;
}