#include <bits/stdc++.h>
using namespace std;
int ans;
char s[10005];
bool flag[26] = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
                 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0};
bool ch[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};
int main() {
  scanf("%s", s);
  int len = strlen(s);
  for (int i = 0; i < len; i++) {
    int c = s[i] - 'A';
    if (flag[c]) {
      printf("NO");
      return 0;
    }
    ans += ch[c];
  }
  if (ans == len || ans == 0)
    printf("YES");
  else
    printf("NO");
  return 0;
}
