#include <iostream>
#include <vector>

int main() {
    using namespace std;
    constexpr int N = 26;
    auto decode = [&](char c, int k) -> char {
        int ord = c - 'A';
        ord = (ord - k) % N;
        ord = (ord + N) % N;
        return 'A' + ord;
    };

    string s;
    cin >> s;
    int n = s.size();
    for (int k = 0; k < n; k++) { cout << decode(s[k], k + 1); }
    cout << endl;
}