#include <bits/stdc++.h>
using namespace std;
const int MAX = 1 << 17;
char s[MAX];
int main() {
  int n;
  scanf("%s", s);
  n = (int)strlen(s);
  int st = 0;
  for (int i = 0; i < n; i++) {
    if (s[i] != 'a') {
      st = 1;
      s[i]--;
    } else if (st)
      break;
  }
  if (!st) s[n - 1] = 'z';
  printf("%s\n", s);
  return 0;
}
