from itertools import combinations, count, accumulate, product
from typing import List
from math import ceil, sqrt
from collections import defaultdict


def main():
    N = int(input())
    primes = list(calc_prime_numbers(1000))
    max_prime = 1
    idx = 0
    while max_prime * primes[idx] <= N:
        max_prime *= primes[idx]
        idx += 1
    print(idx)


def calc_prime_numbers(upper: int) -> List[int]:
    if upper < 2:
        return []
    if upper == 3:
        return [2]
    if upper == 4:
        return [2, 3]
    if 5 <= upper <= 6:
        return [2, 3, 5]
    if 7 <= upper <= 10:
        return [2, 3, 5, 7]
    sqrt_upper = ceil(sqrt(upper))
    primes = []

    prime_flag = [False, True] * (upper // 2 + 1)
    prime_flag[1] = False
    prime_flag[2] = True

    for num in range(3, len(prime_flag)):
        if not prime_flag[num]:
            continue
        if num * 2 >= len(prime_flag):
            continue
        for multi_num in range(num * 2, len(prime_flag), num):
            prime_flag[multi_num] = False
    return (num for num, flag in enumerate(prime_flag) if flag)


if __name__ == "__main__":
    main()