# -*- coding: utf-8 -*-
"""
No.311 z in FizzBuzzString
https://yukicoder.me/problems/no/311

"""
import sys
from sys import stdin
input = stdin.readline


def solve(N):
    fizz = N // 3
    buzz = N // 5
    return fizz * 2 + buzz * 2


def main(args):
    N = int(input())
    ans = solve(N)
    print(ans)


if __name__ == '__main__':
    main(sys.argv[1:])