#include <iostream>
#include <string>
using namespace std;

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