#include <bits/stdc++.h>
using namespace std;
const int N = 1e5 + 5;
int main() {
  long long i, k, z = 0, x = 0;
  string s;
  cin >> s;
  k = s.size();
  for (i = 0; i < k; i++) {
    if (s[i] != 'a') {
      x = 1;
      z = i;
      break;
    }
  }
  if (x == 0) {
    s[k - 1] = 'z';
    cout << s;
    return 0;
  }
  for (i = z; s[i] != 'a' && i < k; i++) {
    s[i] = s[i] - 1;
  }
  cout << s;
}
