#include <bits/stdc++.h>
using namespace std;
bool bz[26] = {1, 0, 0, 0, 1, 1, 0, 1, 1, 0, 1, 1, 1,
               1, 0, 0, 0, 0, 0, 1, 0, 1, 1, 1, 1, 1};
string a;
bool bj;
int main() {
  cin >> a;
  bool c = bz[a[0] - 'A'];
  for (int i = 1; i < a.size(); i++)
    if (bz[a[i] - 'A'] != c) {
      printf("NO");
      return 0;
    }
  printf("YES");
  return 0;
}
