import math

def get_list_primes(n):
    if n == 1:
        return []
    if n == 2:
        return [2]
    
    prime_list = [2]
    num_list = [e + 1 for e in range(2, n, 2)]
    limit = int(n ** 0.5)

    while True:
        leader = num_list[0]
        if limit < leader:
            return prime_list + num_list
        prime_list.append(leader)
        num_list = [e for e in num_list if e % leader != 0]

def judge_prime(n):
    res = None
    count = 0
    
    for i in range(1, int(n ** 0.5) + 1):
        if n % i == 0:
            count += 1
            if n // i != i:
                count += 1
                
    if count > 2:
        res = 0
    else:
        res = 1
        
    return res
        
n = int(input())

prime_list = get_list_primes(n)
len_list = len(prime_list)
res = 0

for i in range(len_list):
    target = (prime_list[i] + 2) ** 0.5
    if math.ceil(target) != math.floor(target):
        continue
    if judge_prime(int(target)) == 1:
        if prime_list[i] == target:
            res += 1
        else:
            res += 2
        
print(res)