#include <iostream>
#include <string>

using namespace std;

int main(int argc, char const *argv[])
{
    int i = 0;
    int shift;
    char ch;
    string str;

    cin >> str;
    while(i != str.length()){
        ch = str[i];
        shift = i+1;
        while(1){
           if((ch - shift) < 'A'){
                shift = shift - (ch - 'A' + 1);
                ch = 'Z';
            }else{
                ch = ch - shift;
                cout << ch;
                break;
            }
        }
        i++;
    }

    cout << endl;
    return 0;
}