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