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