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

int main()
{
    ll N;
    cin >> N;
    
    ll sum = 0;

    for(ll i = 0; i < N; i++)
    {
        if(i % 3 != 0 && i % 5 != 0)sum += i;
    }
    cout << sum << endl;
    return 0;
}