#include <iostream>
#include <iomanip>
#include <string>
#include <vector>
#include <algorithm>
#include <map>
#include <cmath>
#include <queue>
#include <set>

#define rep(i, n) for (int i = 0; i < (n); i++)

using namespace std;
typedef long long int ll;
const int INF = 1000000000;

int main()
{
    int n;
    cin >> n;
    ll ans = 0;
    for (int i = 1; i <= n; i++) {
        if (i % 3 == 0 || i % 5 == 0) continue;
        ans += i;
    }
    cout << ans << endl;
    return 0;
}