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

signed main(){
  cin.tie(nullptr);
  ios::sync_with_stdio(false);

  int N;
  cin >> N;
  N++;
  ll count = 0;
  rep(i, N){
    if(i%3 != 0 && i%5 != 0){
      count += i;
    }
  }
  cout << count << "\n";
}


