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


void solve(long long N){
  long long sum = 0;
  for (long long i = 0; i < N; i++)
    {
      if (i % 3 == 0 || i % 5 == 0)
	continue;
      sum += i;
    }
  cout << sum << endl;
}

// Generated by 1.1.6 https://github.com/kyuridenamida/atcoder-tools  (tips: You use the default template now. You can remove this line by using your custom template)
int main(){
    long long N;
  scanf("%lld",&N);
    solve(N);
    return 0;
}
