#include <bits/stdc++.h>
using namespace std;
int main() {
  ios::sync_with_stdio(false);
  string str = "";
  cin >> str;
  int i = 0;
  while (i < str.length() && str[i] == 'a') i++;
  if (i == str.length()) {
    str[str.length() - 1] = 'z';
    cout << str << endl;
  } else {
    while (i < str.length() && str[i] != 'a') {
      str[i]--;
      i++;
    }
    cout << str << endl;
  }
  return 0;
}
