#include<bits/stdc++.h> //ABC 162_b
#define ll long long
using namespace std;
int main(){
	int n;
	cin>>n;
	ll ans=0;
	for(int i=1;i<=n;i++){
		if(i%3==0||i%5==0)
			continue;
		ans+=i;
	}
	cout<<ans;
	return 0;
}