#include<iostream>
#include<vector>
#include<algorithm>
#include<cmath>
#include<cstdio>
using namespace std;
int main(){
    char s[1025];
    int num;
    cin >> s;
    for(int i=0;s[i]!='\0';i++){
        num = (s[i]-'A')-i-1;
        while(num<0)   num+=26;
        printf("%c",(num+'A'));
    }
    return 0;
}