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