Python :

# coding=utf-8
def construct_plist():
    MAX = 10**6+1
    fl = [0 for _ in range(MAX)]
    prime_list = []
    for i in range(2, MAX):
        if fl[i]:
            continue
        prime_list.append(i)
        for j in range(i, MAX, i):
            fl[j] = 1
    return prime_list

prime_list = construct_plist()
N = int(input())
ANS = 0
LEN = len(prime_list)
q = LEN - 1

for i in range(LEN):
    while i < q and prime_list[i]*prime_list[q]**3 > N:
        q -= 1
    if i >= q:
        break
    ANS += q - i

print(ANS)