import std;

void main() {
    int T;
    readf("%d\n", T);

    string f(string x, string y) {
        string u = x ~ y, v = y ~ x;
        if (u > v) return "X";
        else if (u < v) return "Y";

        auto a = x.length, b = y.length;
        if (a > b) return "X";
        else return "Y";
    }

    foreach (_; 0 .. T) {
        string x, y;
        readf("%s\n%s\n", x, y);

        f(x, y).writeln;
    }
}