#include <bits/stdc++.h>
using namespace std;
char a[100000];
int main() {
  int i = 0;
  cin >> a;
  while (a[i] == 'a') {
    i++;
  }
  if (a[i] == 0) {
    a[i - 1] = 'z';
  }
  for (i; a[i] != 'a' && a[i] != 0; i++) {
    a[i]--;
  }
  cout << a << endl;
  return 0;
}
