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

int main() {

  int N,sum;

  cin >> N;
  for(int i=1; i<N+1; i++ ){
    if(i%3==0){
      continue;
    }

    if(i%5==0){
      continue;
    }


    sum=sum+i;

  }

  cout << sum ;

}
