#include <iostream>
#include <algorithm>
#include <vector>
#include <map>
#include <set>
#include <math.h>
#include <queue>
using namespace std;
typedef long long ll;

int main() {
  ll 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;
  return 0;
}