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