#include <bits/stdc++.h>

using namespace std;

typedef long long ll;

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 << endl;
    return 0;
}