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