This problem is a programming version of Problem 201 from projecteuler.net
For any set of numbers, let be the sum of the elements of .
Consider the set .
There are 20 subsets of B containing three elements, and their sums are:
Some of these sums occur more than once, others are unique.
For a set , let be the set of unique sums of subsets of , in our example we find and .
Now consider the -element set .
has -element subsets.
Determine the sum of all integers which are the sum of exactly one of the -element subsets of , i.e. find .
First line of input contains two integers and . Second line of input contains integers .
Print one integer containing answer to the problem.
1 3 6 8 10 11