#include <bits/stdc++.h>
#define ll long long int
using namespace std;
int main () {
	ll n;
	cin>>n;
	ll i;ll s=0;
	for(i=1;i<=n;i++)
	{
		if(i%3==0 ||  i%5==0)
		continue;
		else
		s+=i;
	}
	cout<<s<<endl;
}

