import java.util.*;

public class Main {

	public static long total(int n) {
		return (long)n * (long)(n + 1) / 2;
	}
	public static void main(String args[]) {
		Scanner sc = new Scanner(System.in);
		int n = sc.nextInt();
		sc.close();
		long ans = 0;
		ans = total(n);
		long rest = 3 * total(n / 3);
		ans -= rest;
		rest = 5 * total(n / 5);
		ans -= rest;
		rest = 15 * total(n / 15);
		ans += rest;
		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