#include <bits/stdc++.h>

using namespace std;

int main() {
  string s;
  cin >> s;
  int n = s.size();
  for (int i = 0; i < n; ++i) {
    int cur = s[i] - 'A';
    int shifted = cur - (i + 1);
    if (shifted < 0) {
      if (shifted % 26 == 0) {
	shifted = 0;
      } else {
	shifted %= 26;
	shifted = 26 + shifted;
      }
    }
    char tmp = shifted + 'A';
    cout << tmp;
  }
  puts("");
  return 0;
}