#include <bits/stdc++.h>
int main() {
  char Linear[] = {'A', 'E', 'Z', 'T', 'Y', 'I', 'F', 'H',
                   'K', 'L', 'M', 'W', 'X', 'V', 'N', '\0'};
  char Curved[] = {'R', 'U', 'O', 'P', 'Q', 'S', 'D', 'G', 'J', 'C', 'B', '\0'};
  int x = 0, i = 0;
  char ch[10];
  scanf("%s", ch);
  if (strlen(ch) == 1) {
    printf("YES");
    return 0;
  } else {
    if (strchr(Linear, ch[0]))
      x = 1;
    else if (Curved, ch[0])
      x = 2;
    if (x == 1) {
      while (i < strlen(ch)) {
        if (strchr(Curved, ch[i])) {
          printf("NO");
          return 0;
        }
        i++;
      }
    } else {
      while (i < strlen(ch)) {
        if (strchr(Linear, ch[i])) {
          printf("NO");
          return 0;
        }
        i++;
      }
    }
  }
  printf("YES");
  return 0;
}
