#include <bits/stdc++.h>
using namespace std;
char str[100005];
int main() {
  cin >> str;
  int l = strlen(str);
  int found = 0;
  int ongoing = 0;
  for (int i = 0; i < l; i++) {
    if (str[i] != 'a' && (found == 0 || (found = 1 && ongoing == 1))) {
      str[i]--;
      ongoing = 1;
    } else if (str[i] == 'a' && ongoing == 1)
      break;
  }
  if (ongoing == 0)
    if (str[l - 1] == 'a') str[l - 1] = 'z';
  cout << str;
}
