#include <bits/stdc++.h>
#define rep(i,n) for (int i = 0; i < (n); ++i)
using namespace std;
using ll = long long;

int main() {
    int N;
    cin >> N;

    ll ans = 0;
    for (ll i = 1; i <= N; i++){
        if (i % 3 != 0 && i % 5 != 0) ans += i;
    }

    cout << ans << endl;
    
}