#include <bits/stdc++.h>
using namespace std;
bool bow[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};
char cxk[11];
int ans[2];
int main() {
  scanf("%s", cxk);
  int i = -1;
  while (cxk[++i]) ans[bow[cxk[i] - 'A']] |= 1;
  printf("%s", ans[0] + ans[1] == 1 ? "YES" : "NO");
  return 0;
}
