
import java.util.Scanner;

public class Main {

    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        long n = sc.nextLong();
        long ans = n * (n+1) / 2;
        long num3, num5, num15;
        num3 =  n / 3;
        num5 = n / 5;
        num15 = n / 15;
        long sub = 3*(num3+1)*num3/2 + 5 * (num5+1)*num5/2 - 15*(num15+1)*num15/2;
        ans -= sub;
        System.out.println(ans);
    }
} import java.util.Scanner; Scanner java.util public class Main {

    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        long n = sc.nextLong();
        long ans = n * (n+1) / 2;
        long num3, num5, num15;
        num3 =  n / 3;
        num5 = n / 5;
        num15 = n / 15;
        long sub = 3*(num3+1)*num3/2 + 5 * (num5+1)*num5/2 - 15*(num15+1)*num15/2;
        ans -= sub;
        System.out.println(ans);
    }
} Main public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        long n = sc.nextLong();
        long ans = n * (n+1) / 2;
        long num3, num5, num15;
        num3 =  n / 3;
        num5 = n / 5;
        num15 = n / 15;
        long sub = 3*(num3+1)*num3/2 + 5 * (num5+1)*num5/2 - 15*(num15+1)*num15/2;
        ans -= sub;
        System.out.println(ans);
    } main {
        Scanner sc = new Scanner(System.in);
        long n = sc.nextLong();
        long ans = n * (n+1) / 2;
        long num3, num5, num15;
        num3 =  n / 3;
        num5 = n / 5;
        num15 = n / 15;
        long sub = 3*(num3+1)*num3/2 + 5 * (num5+1)*num5/2 - 15*(num15+1)*num15/2;
        ans -= sub;
        System.out.println(ans);
    } Scanner sc = new Scanner(System.in); sc new Scanner(System.in) long n = sc.nextLong(); n sc.nextLong() sc.nextLong sc long ans = n * (n+1) / 2; ans n * (n+1) / 2 n * (n+1) n (n+1) n 1 2 long num3 num3 num5 num5 num15; num15 num3 =  n / 3 num3 n / 3 n 3 num5 = n / 5 num5 n / 5 n 5 num15 = n / 15 num15 n / 15 n 15 long sub = 3*(num3+1)*num3/2 + 5 * (num5+1)*num5/2 - 15*(num15+1)*num15/2; sub 3*(num3+1)*num3/2 + 5 * (num5+1)*num5/2 - 15*(num15+1)*num15/2 3*(num3+1)*num3/2 + 5 * (num5+1)*num5/2 3*(num3+1)*num3/2 3*(num3+1)*num3 3*(num3+1)*num3 3 (num3+1) num3 1 num3 2 5 * (num5+1)*num5/2 5 * (num5+1)*num5 5 * (num5+1)*num5 5 (num5+1) num5 1 num5 2 15*(num15+1)*num15/2 15*(num15+1)*num15 15*(num15+1)*num15 15 (num15+1) num15 1 num15 2 ans -= sub ans sub System.out.println(ans) System.out.println System.out System System.out ans String[] args args public class Main {

    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        long n = sc.nextLong();
        long ans = n * (n+1) / 2;
        long num3, num5, num15;
        num3 =  n / 3;
        num5 = n / 5;
        num15 = n / 15;
        long sub = 3*(num3+1)*num3/2 + 5 * (num5+1)*num5/2 - 15*(num15+1)*num15/2;
        ans -= sub;
        System.out.println(ans);
    }
} public class Main {

    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        long n = sc.nextLong();
        long ans = n * (n+1) / 2;
        long num3, num5, num15;
        num3 =  n / 3;
        num5 = n / 5;
        num15 = n / 15;
        long sub = 3*(num3+1)*num3/2 + 5 * (num5+1)*num5/2 - 15*(num15+1)*num15/2;
        ans -= sub;
        System.out.println(ans);
    }
} Main

import java.util.Scanner;

public class Main {

    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        long n = sc.nextLong();
        long ans = n * (n+1) / 2;
        long num3, num5, num15;
        num3 =  n / 3;
        num5 = n / 5;
        num15 = n / 15;
        long sub = 3*(num3+1)*num3/2 + 5 * (num5+1)*num5/2 - 15*(num15+1)*num15/2;
        ans -= sub;
        System.out.println(ans);
    }
}