n = int(input().strip())
if n < len(['a', 'a']):
    print("NO")
else:
    is_prime = True
    i_list = ['a', 'a']  # Represents 2
    while len(i_list) < n:
        i = len(i_list)
        if n % i == 0:
            is_prime = False
            break
        i_list.append('a')
    print("YES" if is_prime else "NO")