Tom has many cigarettes. We hypothesized that he has n cigarettes and smokes them
one by one keeping all the butts. Out of k > 1 butts he can roll a new cigarette.
Now，do you know how many cigarettes can Tom has?
First input is a single line,it's n and stands for there are n testdata.then there are n lines ,each line contains two integer numbers giving the values of n and k.
For each line of input, output one integer number on a separate line giving the maximum number of cigarettes that Peter can have.
3 4 3 10 3 100 5
5 14 124