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