#include<iostream>
#include<string>
using namespace std;
int main(){
	string s; cin >> s;
	for (int i = 0; i < s.size(); i++){
		int c = s[i] - 'A';
		c = (c - (i + 1) % 26 + 26) % 26;
		s[i] = c + 'A';
	}
	cout << s << endl;
	return 0;
}