#include <bits/stdc++.h>
using namespace std;
int N;
string s;
int main() {
  cin >> s;
  int i;
  N = s.length();
  for (i = 0; i < N; i++)
    if (s[i] != 'a') break;
  int st = i;
  if (st == N) {
    for (i = 1; i < N; i++) cout << "a";
    cout << "z"
         << "\n";
    return 0;
  }
  int ed;
  for (ed = i; ed < N; ed++)
    if (s[ed] == 'a') break;
  ed--;
  for (i = st; i <= ed; i++) s[i] = (char)(s[i] - 1);
  cout << s << "\n";
  return 0;
}
