#include <iostream>
#define rep(i, n) for (int i = 0; i < (n); i++)
using namespace std;

typedef long long ll;

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