#include <bits/stdc++.h>
using namespace std;
string str1;
int main() {
  int i, j;
  cin >> str1;
  int limit = str1.size();
  bool f = 0;
  while (j < limit) {
    if (str1[j] == 'a')
      j++;
    else
      break;
  }
  for (i = j; i < limit; i++) {
    if (str1[i] != 'a') {
      str1[i]--;
      f = 1;
    } else
      break;
  }
  if (f)
    cout << str1;
  else {
    str1[limit - 1] = 'z';
    cout << str1;
  }
  return 0;
}
