// Arup Guha
// 8/31/2021
// Used for solution to Question 4 CIS 3362 Fall 2021 Homework #1.

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

int main(void) {

    // Read the plaintext.
    char plain[1000];
    scanf("%s", plain);
    int len = strlen(plain);

    // Hard code keys.
    int a = 15, b = 6;

    // Encrypt and print.
    for (int i=0; i<len; i++)
        printf("%c", (a*((plain[i]-'a'))+b)%26 + 'a');
    printf("\n");

    return 0;
}