Prime Sums#1270
There is a set S = \{x_1, x_2, \ldots, x_n\} and an integer . Count how many sums of elements from the set are prime numbers.
There are several test cases. Each test consists of two lines. The first line contains integers (1 \leq n \leq 20) and (1 \leq k \leq n). The second line contains integers x_1, x_2, \ldots, x_n (1 \leq x_i \leq 5000000).
For each test case, output the number of such sums on a separate line.
Example 1