#include <bits/stdc++.h>
#define rep(i, n) for (int i = 0; i < (int)(n); i++)
using namespace std;
using ll = long long;
using ld = long double;
int main() {
  ll n = 0;
  ll sum = 0;
  cin >> n;
  for (int i = 1; i <= n; i++) {
    if (i % 3 != 0 && i % 5 != 0) {
      sum += i;
    }
  }
  cout << sum << endl;
}