c

#include <stdio.h>
#include <string.h>

void change(char *a, char *b) //str, key
{
    for (int i = 0; i <= strlen(a); i++)
        if (a[i] >= 'A' && a[i] <= 'Z')
        {
            int move = a[i] - 65 + b[i] - 65;
            
            if (move >= 26)
                move -= 26;

            a[i] = 'A' + move;
        }

        else if (a[i] >= 'a' && a[i] <= 'z')
        {
            int move = a[i] - 97 + b[i] - 97;
            
            if (move >= 26)
                move -= 26;

            a[i] = 'a' + move;
        }
}

void bigsmall(char *a, char *b) //str, key
{
    for (int i = 0; i <= strlen(a); i++)
    {
        if (a[i] >= 'A' && a[i] <= 'Z' && b[i] >= 'a' && b[i] <= 'z')
            b[i] -= 32;
        else if (a[i] >= 'a' && a[i] <= 'z' && b[i] >= 'A' && b[i] <= 'Z')
            b[i] += 32;
    }
}

int main()
{
    char str[100001], key[100001];
    scanf("%s %s", str, key);
    
    if (strlen(key) < strlen(str)) //若密鑰字較少，複製
        for (int i = strlen(key), j = 0; i < strlen(str); i++, j++)
            key[i] = key[j];

    bigsmall(str, key);
    change(str,key);
    puts(str);

    return 0;
}