#include <bits/stdc++.h>
using namespace std;
int main() {
  int i, flag = 0;
  char ch[100001];
  cin >> ch;
  int len = strlen(ch);
  for (i = 0; i < len; i++) {
    if (ch[i] != 'a') {
      flag = 1;
      ch[i]--;
    } else {
      if (flag == 1) break;
    }
  }
  if (flag == 0) ch[len - 1] = 'z';
  cout << ch;
}
