#include<iostream>
using namespace std;
int main()
{
	int N;
	cin>>N;
	while(N--)
	{
		int WholeN,k,ciga;
		cin>>WholeN>>k;
		ciga=WholeN;
		while(WholeN/k>0)
		{
			ciga+=WholeN/k;
			WholeN=WholeN%k+WholeN/k;
		}
		cout<<ciga<<endl;




	}
}