#include <iostream>
#include <string>

using namespace std;

int main() {
	string str;

	cin >> str;
	for (int i = 0; i < str.size(); i++) {
		str[i] = 'A' + ((str[i] - 'A' - i - 1) % 26 + 26) % 26;
	}

	cout << str << endl;
	return 0;
}