8.4 Bob, Alice and Three Numbers

Score: 30pts

Time Limit: 1.00 sec

Alice has given Bob an array of distinct integers and his task is to find the number of possible triplets which add up to a given target.

Constraints

\(1 \leq n \leq 1000\)

Input Format

First line contains the number of distinct integers and the target sum

Following line contains the n distinct integers in the array

Following line contains the n distinct integers in the array

Output Format

Output the number of possible triplets

Example 1

Input:

8 0

12 3 1 2 -6 5 -8 6

Output:

3

Explanation:

[-8, 2, 6], [-8, 3, 5], [-6, 1, 5] are the possible triplets which add up to the target sum which is 0.

8 0

12 3 1 2 -6 5 -8 6

Output:

3

Explanation:

[-8, 2, 6], [-8, 3, 5], [-6, 1, 5] are the possible triplets which add up to the target sum which is 0.