#include <bits/stdc++.h>
using namespace std;

int main(){
    string S;
    cin >> S;
    int N = S.size();

    for (int i = 0; i < N; i++){
        int c = S[i]-'A'-i-1;
        c = (c+(26<<20))%26;
        cout << char('A'+c);
    }

    cout << endl;
}