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