#include <iostream>
#include <cstdio>
#include <algorithm>
#include <cmath>

using namespace std;

char str1[70], str2[70];
int num1[70], num2[70];

int main(){
    int t;
    int cnt = 0;
    scanf("%d", &t);
    while(t --){
        cnt ++;
        scanf("%s %s", str1, str2);
        int len = strlen(str1);
        for(int i = 0; i < len; i ++){
            num1[i] = str1[i] - 'a' + 1;
            num2[i] = str2[i] - 'a' + 1;
        }
        printf("Case #%d: ", cnt);
        if(len == 2){
            if(num1[0] - num2[0] == num1[1] - num2[1] && (num1[0] - num2[0]) % 2 == 0)
                printf("YES\n");
            else if(num1[0] - num2[1] == num1[1] - num2[0] && (int)abs((float)num1[0] - (float)num2[1]) % 2)
                printf("YES\n");
            else
                printf("NO\n");
        }
        else{
            int sum = 0;
            for(int i = 0; i < len; i ++){
                sum += num1[i] - num2[i];
            }
            if((int)abs((sum)) % 2 == 0)
                printf("YES\n");
            else
                printf("NO\n");
        }
    }
    return 0;
}