#include <bits/stdc++.h>
using namespace std;
int main() {
  string s;
  int i, len, cnt = 0, t = 0;
  cin >> s;
  len = s.length();
  for (i = 0; i < len; i++) {
    if (s[i] == 'a' && t) break;
    if (s[i] != 'a') {
      s[i] = s[i] - 1;
      t++;
    }
  }
  if (!t) {
    if (s[len - 1] == 'a')
      s[len - 1] = 'z';
    else
      s[len - 1] = s[len - 1] - 1;
  }
  cout << s << endl;
}
