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

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

