#include <iostream>
#include <algorithm>
#include <string>
#include <queue>
#include <vector>
#include <map>
#include <cstdio>
#include <cmath>
using namespace std;

int main() {
	string s;
	cin >> s;
	for (int i = 1; i <= s.size(); i++) {
		int a = int(s[i - 1]) - 65;
		for (int j = 0; j < i; j ++ ) {
		if (a == 0)a = 25;
		else a--;
	}
		//cout << a << endl;
		cout << char(a + 65);
	}
	cout << endl;
	return 0;
}