#include <bits/stdc++.h>
using namespace std;
int main() {
  string s;
  cin >> s;
  int n = s.size();
  int l, r;
  int ans = 0;
  for (int i = 0; i < n; i++)
    if (s[i] != 'a') ans++;
  if (ans == 0) {
    s[n - 1] = 'z';
    cout << s;
    return 0;
  }
  ans = 0;
  for (int i = 0; i < n; i++) {
    if (s[i] != 'a' && ans == 0) l = i, ans++;
    if (i != 0 && s[i] == 'a' && ans == 1) {
      r = i - 1;
      break;
    }
    if (i == n - 1) r = i;
  }
  for (int i = l; i <= r; i++) {
    char a = s[i] - 1;
    s[i] = a;
  }
  cout << s;
  return 0;
}
