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

int main() {

  int N;
  cin >> N;

    int64_t sum = 0;
  for(int i = 1; i <= N; i++){
    if(i % 3 != 0 && i % 5 != 0){
        sum += i;
    }
  }
    cout << sum << endl;
}
