#include <bits/stdc++.h>
using namespace std;
string s;
int main() {
  ios::sync_with_stdio(0);
  cin.tie(0);
  cin >> s;
  int i = 0;
  while (i < ((int)s.size()) && s[i] == 'a') i++;
  if (i == ((int)s.size())) {
    s[i - 1] = 'z';
  } else {
    while (i < ((int)s.size())) {
      if (s[i] == 'a') break;
      s[i] = s[i] - 1;
      i++;
    }
  }
  cout << s << endl;
  return 0;
}
