#include <bits/stdc++.h>
using namespace std;
using ll = long long;

int main() {
  ll n; cin >> n;
  ll sum;
  for(ll i = 1; i<=n; i++){
    if(i%3!=0 || i%5!=0) sum+=i;
  }
  cout << sum << endl;
  
  return 0;
}