#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;
  int sum=0;
  for (int i = 1; i <= N; i++) {
    if (i%3!=0 && i%5!=0){
        sum += i;
    }
  }
  cout << sum << endl;
  return 0;
}
