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

int N;

int main() {
    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;
}