水

#include <iostream>
#include <cstdio>
#include <iomanip>
#include <string>
#include <cstdlib>
#include <cstring>
#include <queue>
#include <set>
#include <vector>
#include <map>
#include <algorithm>
#include <cmath>
#include <stack>
#include <stdlib.h>
#include <stdio.h>

#define INF 0x3f3f3f3f
#define LINF 0x3f3f3f3f3f3f3f3f
#define ll long long
#define ull unsigned long long
#define uint unsigned int
#define l(x) x<<1
#define r(x) x<<1|1
#define ms(a,b) memset(a,b,sizeof(a))

using namespace std;

int x;
int n, m;
char str1[500], str2[500], str3[500];
int len;

int main() {
	scanf("%d", &x);
	for (int i = 1; i <= x; i++) {
		scanf("%d%d", &n,&m);
		scanf("%s%s%s", str1, str2,str3);

		len = ((str2[0] - str1[0]) % 26 + 26) % 26;
		len = 26 - len;
		for (int i = 0; i < m; i++) {
			str3[i] = (str3[i]-'A' + len) % 26+'A';
		}
		printf("Case #%d: %s\n",i, str3);
	}

	return 0;
}