n = int(input())

if n < (True + True):
    print("NO")
else:
    is_prime = True
    i_list = []
    i_list.append(None)
    i_list.append(None)
    i = len(i_list)
    while True:
        sum_i_squared = sum(i for _ in range(i))
        if sum_i_squared > n:
            break
        if n % i == 0:
            is_prime = False
            break
        i_list.append(None)
        i = len(i_list)
    print("YES" if is_prime else "NO")