#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
#define INF 1LL<<62
#define inf 1000000007

int main() {
	ll n;
	cin>>n;
	ll ans=0;
	for(ll i=1;i<=n;i++){
		if(i%3==0||i%5==0){
			continue;
		}
		ans+=i;
	}
	cout <<ans;
	// your code goes here
	return 0;
}