#include <bits/stdc++.h>
using namespace std;
string s;
map<char, bool> p;
int main() {
  ios::sync_with_stdio(false);
  p['A'] = 1;
  p['E'] = 1;
  p['F'] = 1;
  p['H'] = 1;
  p['I'] = 1;
  p['K'] = 1;
  p['L'] = 1;
  p['M'] = 1;
  p['N'] = 1;
  p['T'] = 1;
  p['V'] = 1;
  p['W'] = 1;
  p['X'] = 1;
  p['Y'] = 1;
  p['Z'] = 1;
  cin >> s;
  int sum = 0;
  for (int i = 0; i < s.size(); i++) sum += p[s[i]];
  if (sum == s.size() or sum == 0)
    cout << "YES";
  else
    cout << "NO";
  return 0;
}
