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

ll solve() {
    ll N;
    cin >> N;
    ll ans = 0;
    for ( ll i = 1; i <= N; i++ ) {
        if ( i % 3 == 0 || i % 5 == 0 ) continue;
        ans += i;
    }
    return ans;
}

int main() {
    auto ans = solve();
    cout << ans << "\n";
    return 0;
}