#include<bits/stdc++.h>

using namespace std;
typedef long long ll;
typedef double d;

int main()
{
	ll n;
	cin>>n;
	ll sum=0;
	for(int i=1;i<=n;i++){
        if(i%3!=0&&i%5!=0)
            sum+=i;
	}
	cout<<sum;
	return 0;
}

