#include <bits/stdc++.h>
using namespace std;
int main() {
  string s;
  int move, flag = 0;
  cin >> s;
  move = 0;
  while (s[move] == 'a' and move < s.size()) {
    move++;
    flag = 1;
  }
  while (s[move] != 'a' and move < s.size()) {
    s[move]--;
    move++;
    flag = 0;
  }
  if (flag == 1) {
    s[s.size() - 1] = 'z';
  }
  cout << s << endl;
  return 0;
}
