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

int main() {
    ll n; cin >> n;
    ll ans = 0;

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

    cout << ans;
}