#include <iostream>
#include <string>

using namespace std;

string decrypt(string encrypted) {
    string decrypted = "";
    int shift = 1;
    for (int i = 0; i < encrypted.length(); i++) {
        char decryptedChar = encrypted[i] - shift;
        if (decryptedChar < 'A') {
            decryptedChar += 26;
        }
        decrypted += decryptedChar;
        shift = (i + 1) % 26 + 1;
    }
    return decrypted;
}

int main() {
    string encrypted;
    cin >> encrypted;
    string decrypted = decrypt(encrypted);
    cout << decrypted << endl;
    return 0;
}