#include <bits/stdc++.h>
using namespace std;
int main() {
  string s;
  cin >> s;
  int len = s.length();
  int flag = 0;
  int first, second;
  for (int i = 0; i < len; i++) {
    if (s[i] == 'a' && !flag) continue;
    if (flag && s[i] == 'a') break;
    flag = 1;
    int aa = (int)s[i];
    aa--;
    s[i] = (char)aa;
  }
  if (!flag) {
    s[len - 1] = 'z';
  }
  cout << s;
}
