#if !__INCLUDE_LEVEL__

#include __FILE__


struct Solver {
string s,t;

void XY(int x,int y){
    x+=y;
    if(x%2==0)cout<<'X'<<endl;
    else cout<<'Y'<<endl;
    return ;
}

ll f(int l1,int r1,int l2,int r2){
    bool sw=0;
    if(r1-l1>r2-l2){
        swap(l1,l2);swap(r1,r2);
        swap(s,t);
        sw=1;
    }
    if(r1==l1){
        XY(sz(s)<sz(t),sw);
        return 0;
    }
    int now=l2;
    rep(i,l1,r1){
        if(s[i]!=t[now]){
            XY(s[i]<t[now],sw);
            return 0;
        }
        now++;
    }
    if(sw){
        swap(s,t);
        f(l2+(r1-l1),r2,l1,r1);
    }
    else{
        f(l1,r1,l2+(r1-l1),r2);
    }

    return 0;
}
void solve() {
    cin>>s>>t;
    int n=sz(s),m=sz(t);
    int nm=max(n,m);
    rep(i,nm){
        if(s[i%n]<t[i%m]){
            cout<<'Y'<<endl;
            return ;
        }
        else if(s[i%n]>t[i%m]){
            cout<<'X'<<endl;
            return ;
        }
    }
    f(0,sz(s),0,sz(t));
    
}};

signed main() {
    int ts = 1;
    scanf("%lld",&ts);
    rep(ti,ts) {
        Solver solver;
        solver.solve();
    }
  return 0;
}

#else

#include <bits/stdc++.h>
#include <atcoder/all>
using namespace atcoder;
// #include <ext/pb_ds/assoc_container.hpp>
// #include <ext/pb_ds/tree_policy.hpp>
// using namespace __gnu_pbds;

using namespace std;

#define int ll

using ll=long long;
using ld = long double;
using uint = unsigned;
using ull = unsigned long long;
using P=pair<int,int>;
using TP=tuple<int,int,int>;
template <class T> using V = vector<T>;
template <class T> using max_heap = priority_queue<T>;
template <class T> using min_heap = priority_queue<T, vector<T>, greater<>>;

#define FOR1(a) for (ll _ = 0; _ < ll(a); ++_)
#define FOR2(i, a) for (ll i = 0; i < ll(a); ++i)
#define FOR3(i, a, b) for (ll i = a; i < ll(b); ++i)
#define FOR4(i, a, b, c) for (ll i = a; i < ll(b); i += (c))
#define FOR1_R(a) for (ll i = (a)-1; i >= ll(0); --i)
#define FOR2_R(i, a) for (ll i = (a)-1; i >= ll(0); --i)
#define FOR3_R(i, a, b) for (ll i = (b)-1; i >= ll(a); --i)
#define FOR4_R(i, a, b, c) for (ll i = (b)-1; i >= ll(a); i -= (c))
#define overload4(a, b, c, d, e, ...) e
#define rep(...) overload4(__VA_ARGS__, FOR4, FOR3, FOR2, FOR1)(__VA_ARGS__)
#define rrep(...) overload4(__VA_ARGS__, FOR4_R, FOR3_R, FOR2_R, FOR1_R)(__VA_ARGS__)
#define fore(i,a) for(auto &i:a)

#define all(x) x.begin(),x.end() 
#define sz(x) ((int)(x).size())
#define bp(x) (__builtin_popcountll((long long)(x)))
#define elif else if
#define mpa make_pair
#define bit(n) (1LL<<(n))
#define LB(c, x) distance((c).begin(), lower_bound(all(c), (x)))
#define UB(c, x) distance((c).begin(), upper_bound(all(c), (x)))
#define UNIQUE(x) sort(all(x)), x.erase(unique(all(x)), x.end())

template<class T>bool chmax(T &a, const T &b) { if (a<b) { a=b; return 1; } return 0; }
template<class T>bool chmin(T &a, const T &b) { if (b<a) { a=b; return 1; } return 0; }
template<typename T>istream& operator>>(istream&i,vector<T>&v){rep(j,sz(v))i>>v[j];return i;}
template<typename T>string join(const T&v,const string& d=""){stringstream s;rep(i,sz(v))(i?s<<d:s)<<v[i];return s.str();}
template<typename T>ostream& operator<<(ostream&o,const vector<T>&v){if(sz(v))o<<join(v," ");return o;}
template<typename T1,typename T2>istream& operator>>(istream&i,pair<T1,T2>&v){return i>>v.first>>v.second;}
template<typename T1,typename T2>ostream& operator<<(ostream&o,const pair<T1,T2>&v){return o<<v.first<<","<<v.second;}
template<typename T1,typename T2>bool mins(T1& x,const T2&y){if(x>y){x=y;return true;}else return false;}
template<typename T1,typename T2>bool maxs(T1& x,const T2&y){if(x<y){x=y;return true;}else return false;}
template<typename Tx, typename Ty>Tx dup(Tx x, Ty y){return (x+y-1)/y;}
template<typename T>ll suma(const vector<T>&a){ll res(0);for(auto&&x:a)res+=x;return res;}
template<typename T>ll suma(const V<V<T>>&a){ll res(0);for(auto&&x:a)res+=suma(x);return res;}
template<typename T>void uni(T& a){sort(rng(a));a.erase(unique(rng(a)),a.end());}
template<typename T>void prepend(vector<T>&a,const T&x){a.insert(a.begin(),x);}

const int INF = 1001001001;
const ll INFL = 3e18;
const int MAX = 2e6+5;


#endif