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

#define REP(i,n) for(int (i)=0;(i)<(int)(n);++(i))

char rot(char ch, int n) {
	n %= 26;
	int i = ch - 'A';
	i = (i - n);
	i = ((i % 26) + 26) % 26;
	return 'A' + i;
}

int main() {
	string s;
	cin >> s;
	REP(i, s.size()) {
		s[i] = rot(s[i], i + 1);
	}
	cout << s << endl;
}