#include <bits/stdc++.h>
using namespace std;
const int MAXN = 1e6 + 10;
long long a[MAXN];
int main() {
  ios::sync_with_stdio(false);
  string s;
  cin >> s;
  int ans = 0;
  int st = 0;
  while (s[st] == 'a' and st < s.length()) st++;
  if (st == s.length()) {
    s[s.length() - 1] = 'z';
    cout << s << endl;
    return 0;
  }
  ans = st;
  for (int i = st; i < s.length(); i++)
    if (s[i] == 'a')
      break;
    else
      ans = i;
  for (int i = st; i <= ans and i < s.length(); i++) s[i]--;
  cout << s << endl;
  return 0;
}
