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