#include <vector>
#include <string>
#include <algorithm>
#include <numeric>
#include <iostream>
#include <cstdlib>
#include <cstring>
#include <utility>
#include <list>
#include <map>
#include <queue>
#include <iterator>
#include <cmath>
#include <iomanip>
using namespace std;

using ull = unsigned long long;
using ll = long long;

int main()
{
    string s;
    cin >> s;

    string data = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";

    for(int i =0; i < s.size(); ++i)
    {
        int pos = data.find(s.at(i));
        int tmp = (i+1) % 26;
        if(pos - tmp >= 0)
            pos -= tmp;
        else
        {
            pos = 26 - (tmp - pos);
        }

        cout << data.at(pos);
    }

    cout << endl;
}