#include <bits/stdc++.h>
using namespace std;
string s;
int main() {
  cin >> s;
  int len = s.length();
  bool ok = false;
  for (int i = 0; i < len; i++) {
    if (s[i] != 'a') ok = true;
  }
  if (!ok) {
    s[len - 1] = 'z';
    cout << s << endl;
    return 0;
  }
  for (int i = 0; i < len; i++) {
    if (s[i] != 'a') {
      for (int j = i; j < len; j++) {
        if (s[j] == 'a') break;
        char ch = s[j];
        ch--;
        s[j] = ch;
      }
      break;
    }
  }
  cout << s << endl;
  return 0;
}
