#include <iostream>
using namespace std;

int main() {
    string s;
    cin >> s;
    for(int i = 0;i < s.size();i++) {
        int c = s[i] - (i + 1) % 26;
        if(c - 'A' < 0)
            c += 26;
        cout << char(c);
    }
    cout << endl;
}