#include <bits/stdc++.h>
using namespace std;
int main() {
  bool check = false;
  int x(0);
  string s;
  cin >> s;
  for (int i = 0; i < s.size(); i++) {
    x++;
    if (s[i] != 'a') {
      s[i] = char(int(s[i] - 1));
      check = true;
    } else {
      if (check) break;
      if (x == (s.size())) s[x - 1] = 'z';
    }
  }
  cout << s;
  return 0;
}
