#include <bits/stdc++.h>
using namespace std;
;
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  int f, i;
  f = i = 0;
  string s;
  cin >> s;
  while (s[i] == 'a' && i < s.size()) i++;
  while (s[i] != 'a' && i < s.size()) {
    s[i] = (char)(s[i] - 1);
    f = 1;
    i++;
  }
  if (!f) s[s.size() - 1] = 'z';
  cout << s << '\n';
  cout.flush();
}
