C++ :

#include<iostream>
using namespace std;
int main()
{
	int x,y,time=0;
	cin>>x>>y;
	while (x>=0)
	{
		x-=y;
		time++;
		if (x<=0) break;
		x+=1;
		time++;
	}
	cout<<time<<endl;
	return 0;
}