Lenny likes to play the game of lotto. In the lotto game, he picks a list of N unique numbers in the range from 1 to M. If his list matches the list of numbers that are drawn, he wins the big prize.
Lenny has a scheme that he thinks is likely to be lucky. He likes to choose his list so that each number in it is at least twice as large as the one before it. So, for example, if N = 4 and M = 10, then the possible lucky lists Lenny could like are:
1 2 4 8
1 2 4 9
1 2 4 10
1 2 5 10
Thus Lenny has four lists from which to choose.
Your job, given N and M, is to determine from how many lucky lists Lenny can choose.