#include<bits/stdc++.h>
using namespace std;
#define ll long long

int main(){

	ios_base::sync_with_stdio(false);
    cin.tie(NULL);

    ll n;
    cin >> n;

    ll ans = 0;
    for(ll i=1;i<=n;++i){
    	if(!((i%3 == 0) || (i%5 == 0))){
    		ans+=i;
    	}
    }
    cout << ans << "\n";

	return 0;
}