#include <bits/stdc++.h>
using namespace std;
int main() {
  string s;
  cin >> s;
  int i = 0, l;
  l = s.length();
  while ((s[i] == 'a') && (i <= l - 1)) i++;
  if (i == l) {
    s[i - 1] = 'z';
    cout << s;
    return 0;
  }
  while ((s[i] != 'a') && (i < l)) {
    s[i]--;
    i++;
  }
  cout << s;
}
