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