#include <cstdio>
#include <cstring>

char enc[100005], plain[100005];

void alg() {
    int nEnc = strlen(enc);
    int nPlain = strlen(plain);
    for (int i = 0; i < nPlain; ++i) {
        int sh = enc[i % nEnc] - 'A'  + 1;
        int cur = plain[i] - 'A';
        cur = (cur + sh) % 26;
        putchar(cur + 'A');
    }
    putchar('\n');
}

int main() {
    while (scanf("%s", enc) != EOF) {
        if (enc[0] == '0') {
            return 0;
        }
        scanf("%s", plain);
        alg();
    }
}