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

string convertString(string a,int n){
    int currentNum;
    string list[26] = {"A","B","C","D","E","F","G","H","I","J","K","L","M","N","O","P","Q","R","S","T","U","V","W","X","Y","Z"};
    for (int i = 0; i < 26; i++) {
        if(list[i] == a){
            currentNum = i;
            break;
        }
    }
    currentNum -= n;
    while(currentNum < 0){
        currentNum += 26;
    }
    return list[currentNum%26];
}

int main(int argc, const char * argv[]) {
    string s;
    cin >> s;
    string result;
    string tmp;
    for (int i = 0; i < s.length(); i++) {
        tmp = s[i];
        result += convertString(tmp,i+1);
    }
    cout << result;
    cout << "\n";
}