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

int main(void) {
	string S;
	cin >> S;
	int N = S.size();
	
	for(int i = 0; i < N; ++i) {
		int v = (S[i] - 'A');
		v = (v - (i + 1) % 26 + 26) % 26;
		S[i] = ('A' + v);
	}
	
	cout << S << endl;
	return 0;
}