#include <bits/stdc++.h>
using namespace std;
int main() {
  string s;
  cin >> s;
  int n = s.length();
  bool sign = false;
  for (int i = 0; i < n; i++) {
    if (s[i] == 'a' && !sign) continue;
    if (s[i] == 'a' && sign) break;
    s[i]--;
    sign = true;
  }
  if (!sign) s[n - 1] = 'z';
  cout << s << '\n';
}
