
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);
    }
}
/tmp/hf-datasets-cache/medium/datasets/42704881117311-config-parquet-and-info-qiankunmu-Project_CodeNet-896c9d36/hub/datasets--qiankunmu--Project_CodeNet_Python800_and_Java250/snapshots/c899fde44a77ba1cc14973ed3de064e4ff3aadc7/Project_CodeNet_Java250.tar.gz