Input contains several cases, each of which occupies 3 lines. The first line
contains two non-negative integers N and K. The next line has N positive integers
M1, M2, .... Mn, followed by a line with N non-negative integers P1, P2, .... Pn.
It is guaranteed that K = P1 + P2 + ... + Pn. You may also assume that the total
number of balls in any of the cases does not exceed 50.
Subsequent test cases are separated with a single blank line.
The input is terminated with two -1's. This case is not to be processed.