#include <bits/stdc++.h>
using namespace std;

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