Multiset Sum

Given a list of unique positive integers nums and a positive integer k, return the number of unique combinations that sum up to k. You may reuse numbers when creating combinations.

Constraints

• n ≤ 25 where n is the length of nums
• 1 ≤ nums[i] ≤ 250 for all 0 ≤ i < n
• 1 ≤ k ≤ 500

https://binarysearch.com/problems/Multiset-Sum

Examples

Example 1

Input

• nums = [1, 2, 3]
• k = 2

Output

• answer = 2

Explanation

We can make 2 with [1, 1] and [2].

Solution