#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 = 1e9;

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

  cout << ans << endl;
  return 0;
}
