#include<iostream>
#include<stdio.h>

using namespace std;

int main(){

    string str;
    cin>> str;

    int len = str.size();

    int add=0;
    for(int i=0; i<len; i++){
        str[i] = 'A' +((str[i] - 'A' - (i+1))%26 + 26 )%26;
    }

    cout<< str;
    return 0;
}