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

using ll=long long;
const ll MOD=1000000007;

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