import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        Long n;
        Scanner sc = new Scanner(System.in);
        n = sc.nextLong();
        Long sum = n*(n+1)/2-(n-n%3+3)*(n/3)/2-(n-n%5+5)*(n/5)/2+(n-n%15+15)*(n/15)/2;
        System.out.println(sum);
    }
}

/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