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