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

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