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

int main() {
    int n;
    cin >> n;
    int64_t ans = 0;
    for (int i = 1; i <= n; i++) {
        if (i % 3 != 0 && i % 5 != 0) ans += i;
    }
    cout << ans << endl;
}