# -*- coding: utf-8 -*-

import sys

import math

import os

import itertools

import string

import heapq

import _collections

from collections import Counter

from collections import defaultdict

from functools import lru_cache

import bisect

import re

import queue

from decimal import *





class Scanner():

    @staticmethod

    def int():

        return int(sys.stdin.readline().rstrip())



    @staticmethod

    def string():

        return sys.stdin.readline().rstrip()



    @staticmethod

    def map_int():

        return [int(x) for x in Scanner.string().split()]



    @staticmethod

    def string_list(n):

        return [eval(input()) for i in range(n)]



    @staticmethod

    def int_list_list(n):

        return [Scanner.map_int() for i in range(n)]



    @staticmethod

    def int_cols_list(n):

        return [int(eval(input())) for i in range(n)]





class Math():

    @staticmethod

    def gcd(a, b):

        if b == 0:

            return a

        return Math.gcd(b, a % b)



    @staticmethod

    def lcm(a, b):

        return (a * b) // Math.gcd(a, b)



    @staticmethod

    def divisor(n):

        res = []

        i = 1

        for i in range(1, int(n ** 0.5) + 1):

            if n % i == 0:

                res.append(i)

                if i != n // i:

                    res.append(n // i)

        return res



    @staticmethod

    def round_up(a, b):

        return -(-a // b)



    @staticmethod

    def is_prime(n):

        if n < 2:

            return False

        if n == 2:

            return True

        if n % 2 == 0:

            return False

        d = int(n ** 0.5) + 1

        for i in range(3, d + 1, 2):

            if n % i == 0:

                return False

        return True





def pop_count(x):

    x = x - ((x >> 1) & 0x5555555555555555)

    x = (x & 0x3333333333333333) + ((x >> 2) & 0x3333333333333333)

    x = (x + (x >> 4)) & 0x0f0f0f0f0f0f0f0f

    x = x + (x >> 8)

    x = x + (x >> 16)

    x = x + (x >> 32)

    return x & 0x0000007f





MOD = int(1e09) + 7

INF = int(1e15)





def solve():

    N = Scanner.int()

    ans = 0

    for i in range(1, N+1):

        if i % 3 == 0 or i % 5 == 0:

            continue

        ans += i

    print(ans)





def main():

    # sys.stdin = open("sample.txt")

    solve()





if __name__ == "__main__":

    main()

# -*- coding: utf-8 -*-

import sys

import math

import os

import itertools

import string

import heapq

import _collections

from collections import Counter

from collections import defaultdict

from functools import lru_cache

import bisect

import re

import queue

from decimal import *





class Scanner():

    @staticmethod

    def int():

        return int(sys.stdin.readline().rstrip())



    @staticmethod

    def string():

        return sys.stdin.readline().rstrip()



    @staticmethod

    def map_int():

        return [int(x) for x in Scanner.string().split()]



    @staticmethod

    def string_list(n):

        return [Scanner.string() for i in range(n)]



    @staticmethod

    def int_list_list(n):

        return [Scanner.map_int() for i in range(n)]



    @staticmethod

    def int_cols_list(n):

        return [Scanner.int() for i in range(n)]





class Math():

    @staticmethod

    def gcd(a, b):

        if b == 0:

            return a

        return Math.gcd(b, a % b)



    @staticmethod

    def lcm(a, b):

        return (a * b) // Math.gcd(a, b)



    @staticmethod

    def divisor(n):

        res = []

        i = 1

        for i in range(1, int(n ** 0.5) + 1):

            if n % i == 0:

                res.append(i)

                if i != n // i:

                    res.append(n // i)

        return res



    @staticmethod

    def round_up(a, b):

        return -(-a // b)



    @staticmethod

    def is_prime(n):

        if n < 2:

            return False

        if n == 2:

            return True

        if n % 2 == 0:

            return False

        d = int(n ** 0.5) + 1

        for i in range(3, d + 1, 2):

            if n % i == 0:

                return False

        return True





def pop_count(x):

    x = x - ((x >> 1) & 0x5555555555555555)

    x = (x & 0x3333333333333333) + ((x >> 2) & 0x3333333333333333)

    x = (x + (x >> 4)) & 0x0f0f0f0f0f0f0f0f

    x = x + (x >> 8)

    x = x + (x >> 16)

    x = x + (x >> 32)

    return x & 0x0000007f





MOD = int(1e09) + 7

INF = int(1e15)





def solve():

    N = Scanner.int()



    S = N * (N + 1) // 2

    a = N // 3

    A = a * (a + 1) // 2 * 3

    b = N // 5

    B = b * (b + 1) // 2 * 5

    c = N // 15

    C = c * (c + 1) // 2 * 15

    print((S - A - B + C))





def main():

    # sys.stdin = open("sample.txt")

    solve()





if __name__ == "__main__":

    main()

# -*- coding: utf-8 -*-
import sys
import math
import os
import itertools
import string
import heapq
import _collections
from collections import Counter
from collections import defaultdict
from functools import lru_cache
import bisect
import re
import queue
from decimal import *


class Scanner:
    @staticmethod
    def int():
        return int(sys.stdin.readline().rstrip())

    @staticmethod
    def string():
        return sys.stdin.readline().rstrip()

    @staticmethod
    def map_int():
        return [int(x) for x in Scanner.string().split()]

    @staticmethod
    def string_list(n):
        return [eval(input()) for i in range(n)]

    @staticmethod
    def int_list_list(n):
        return [Scanner.map_int() for i in range(n)]

    @staticmethod
    def int_cols_list(n):
        return [int(eval(input())) for i in range(n)]


class Math:
    @staticmethod
    def gcd(a, b):
        if b == 0:
            return a
        return Math.gcd(b, a % b)

    @staticmethod
    def lcm(a, b):
        return (a * b) // Math.gcd(a, b)

    @staticmethod
    def divisor(n):
        res = []
        i = 1
        for i in range(1, int(n**0.5) + 1):
            if n % i == 0:
                res.append(i)
                if i != n // i:
                    res.append(n // i)
        return res

    @staticmethod
    def round_up(a, b):
        return -(-a // b)

    @staticmethod
    def is_prime(n):
        if n < 2:
            return False
        if n == 2:
            return True
        if n % 2 == 0:
            return False
        d = int(n**0.5) + 1
        for i in range(3, d + 1, 2):
            if n % i == 0:
                return False
        return True


def pop_count(x):
    x = x - ((x >> 1) & 0x5555555555555555)
    x = (x & 0x3333333333333333) + ((x >> 2) & 0x3333333333333333)
    x = (x + (x >> 4)) & 0x0F0F0F0F0F0F0F0F
    x = x + (x >> 8)
    x = x + (x >> 16)
    x = x + (x >> 32)
    return x & 0x0000007F


MOD = int(1e09) + 7
INF = int(1e15)


def solve():
    N = Scanner.int()
    ans = 0
    for i in range(1, N + 1):
        if i % 3 == 0 or i % 5 == 0:
            continue
        ans += i
    print(ans)


def main():
    # sys.stdin = open("sample.txt")
    solve()


if __name__ == "__main__":
    main()

# -*- coding: utf-8 -*-
import sys
import math
import os
import itertools
import string
import heapq
import _collections
from collections import Counter
from collections import defaultdict
from functools import lru_cache
import bisect
import re
import queue
from decimal import *


class Scanner:
    @staticmethod
    def int():
        return int(sys.stdin.readline().rstrip())

    @staticmethod
    def string():
        return sys.stdin.readline().rstrip()

    @staticmethod
    def map_int():
        return [int(x) for x in Scanner.string().split()]

    @staticmethod
    def string_list(n):
        return [Scanner.string() for i in range(n)]

    @staticmethod
    def int_list_list(n):
        return [Scanner.map_int() for i in range(n)]

    @staticmethod
    def int_cols_list(n):
        return [Scanner.int() for i in range(n)]


class Math:
    @staticmethod
    def gcd(a, b):
        if b == 0:
            return a
        return Math.gcd(b, a % b)

    @staticmethod
    def lcm(a, b):
        return (a * b) // Math.gcd(a, b)

    @staticmethod
    def divisor(n):
        res = []
        i = 1
        for i in range(1, int(n**0.5) + 1):
            if n % i == 0:
                res.append(i)
                if i != n // i:
                    res.append(n // i)
        return res

    @staticmethod
    def round_up(a, b):
        return -(-a // b)

    @staticmethod
    def is_prime(n):
        if n < 2:
            return False
        if n == 2:
            return True
        if n % 2 == 0:
            return False
        d = int(n**0.5) + 1
        for i in range(3, d + 1, 2):
            if n % i == 0:
                return False
        return True


def pop_count(x):
    x = x - ((x >> 1) & 0x5555555555555555)
    x = (x & 0x3333333333333333) + ((x >> 2) & 0x3333333333333333)
    x = (x + (x >> 4)) & 0x0F0F0F0F0F0F0F0F
    x = x + (x >> 8)
    x = x + (x >> 16)
    x = x + (x >> 32)
    return x & 0x0000007F


MOD = int(1e09) + 7
INF = int(1e15)


def solve():
    N = Scanner.int()
    S = N * (N + 1) // 2
    a = N // 3
    A = a * (a + 1) // 2 * 3
    b = N // 5
    B = b * (b + 1) // 2 * 5
    c = N // 15
    C = c * (c + 1) // 2 * 15
    print((S - A - B + C))


def main():
    # sys.stdin = open("sample.txt")
    solve()


if __name__ == "__main__":
    main()

-        return [eval(input()) for i in range(n)] +        return [Scanner.string() for i in range(n)] -        return [int(eval(input())) for i in range(n)] +        return [Scanner.int() for i in range(n)] -    ans = 0 -    for i in range(1, N + 1): -        if i % 3 == 0 or i % 5 == 0: -            continue -        ans += i -    print(ans) +    S = N * (N + 1) // 2 +    a = N // 3 +    A = a * (a + 1) // 2 * 3 +    b = N // 5 +    B = b * (b + 1) // 2 * 5 +    c = N // 15 +    C = c * (c + 1) // 2 * 15 +    print((S - A - B + C))