import sys

input=sys.stdin.readline
write=sys.stdout.write

T=int(input())

Ans=[""]*T
for t in range(T):
    x=input()[:-1]
    y=input()[:-1]

    if x+y==y+x:
        Ans[t]="X" if len(x)>len(y) else "Y"
    elif x+y>y+x:
        Ans[t]="X"
    else:
        Ans[t]="Y"

write("\n".join(Ans))