0187. Stifling the Mutiny
Time limit : 1000 ms
Memory limit : 64 mb
A group of pirates is travelling in a convoy of ships, sailing in a row. However, the pirate captain is starting to lose control, and some disloyal pirates are ready to mute. As soon as on any ship S, the number of loyal pirates on S is outnumbered by the combined number of disloyal pirates on $S$, the previous ship (if $S$ is not the rst), and the next ship (if $S$ is not the last) in the convoy, the disloyal pirates on these ships will row to $S$ and take it over. To prevent an outbreak of mutiny, the captain decides to distribute the loyal and disloyal pirates over the ships in such a way that the disloyal pirates cannot capture any ship. Of course, each ship must have at least one loyal pirate to operate the ship.
input: The rst line of the input contains a single number: the number of test cases to follow. Each test case has the following format: One line with two integers n and k, where ($1 \le n \le 15 , n \le k \le 40$). The rst number is the number of ships; the second number is the total number of pirates (whether loyal or disloyal) in the convoy.
Output: For every test case in the input, the output should contain one integer on a single line: the maximum number of disloyal pirates that the captain can distribute over the ships such that the disloyal pirates cannot capture any ship.