import java.util.Scanner;
public class Main {
	public static void main(String[] args) {
	        Scanner sc = new Scanner(System.in);
	        int t = sc.nextInt();
	        for(int i = 0; i < t; i++){
                String x = sc.next();
                String y = sc.next();
                int p = (x + y).compareTo(y + x);
                if(p > 0){
                    System.out.println("X");
                }
                else if (p < 0){
                    System.out.println("Y");
                }
                else{
                    if(x.length() > y.length()){
                        System.out.println("X");
                    }
                    else{
                        System.out.println("Y");
                    }
                }
				
	        }
	    }
}