#include <bits/stdc++.h>
using namespace std;
int main() {
  string s;
  cin >> s;
  bool change = false;
  bool changed = false;
  for (char &c : s) {
    if (!change && c != 'a') change = true;
    if (change && c == 'a') break;
    if (change) {
      c--;
      changed = true;
    }
  }
  if (!changed) (*s.rbegin()) = 'z';
  cout << s;
}
