#include <bits/stdc++.h>
#pragma comment(linker, "/STACK:16777216")
using namespace std;
int main() {
  string s;
  cin >> s;
  int i = 0;
  while (i < s.size() && s[i] == 'a') {
    i++;
  }
  if (i == s.size()) {
    s[i - 1] = 'z';
    cout << s << endl;
    return 0;
  }
  while (i < s.size() && s[i] != 'a') {
    s[i]--;
    i++;
  }
  cout << s << endl;
  return 0;
}
