#include <iostream>

using namespace std;

int n, k;

int main()
{
	cin>> n >> k;
	if (k >= n)
	cout<<2;
	else
		if (2 * n % k)
			cout<< 2 * n / k + 1;
		else
		    cout<< 2 * n / k;
	return 0;
}