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

const int INF = 1001001001;

ll pow(ll base, ll order) {
	ll ans = 1;
	rep(i,order - 1) ans *= base;
	return ans;
}

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

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