#include <bits/stdc++.h>
using namespace std;
string a;
int main() {
  cin >> a;
  bool f[28];
  memset(f, 0, sizeof(f));
  f['A' - 'A' + 1] = 1;
  f['E' - 'A' + 1] = 1;
  f['F' - 'A' + 1] = 1;
  f['H' - 'A' + 1] = 1;
  f['I' - 'A' + 1] = 1;
  f['K' - 'A' + 1] = 1;
  f['L' - 'A' + 1] = 1;
  f['M' - 'A' + 1] = 1;
  f['N' - 'A' + 1] = 1;
  f['T' - 'A' + 1] = 1;
  f['V' - 'A' + 1] = 1;
  f['W' - 'A' + 1] = 1;
  f['X' - 'A' + 1] = 1;
  f['Y' - 'A' + 1] = 1;
  f['Z' - 'A' + 1] = 1;
  int sum = 0, l = a.size();
  for (int i = 0; i < l; i++) sum += f[a[i] - 'A' + 1];
  if (sum == l || sum == 0)
    cout << "YES" << endl;
  else
    cout << "NO" << endl;
  return 0;
}
