学步园

#include<stdio.h>
#include<stdlib.h>
int main()
{
	int n,k;
	while(scanf("%d%d",&n,&k)!=EOF)
	{
	int b,r;
	if(n<=k)
	printf("2\n");
    else
    {
	b=n*2/k;
    r=2*n;
	r%=k;
    if(r==0)
    printf("%d\n",b);
    else
    printf("%d\n",b+1);
	}
	}
	return 0;
}