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

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