You are given an integer array coins and an integer amount. Return the number of combinations that make up that amount. You may use coins in any quantity.

Example 1:

Input coins: 1 2 5
Amount: 5
Output: 4

Example 2:

Input coins: 2
Amount: 3
Output: 0

Input format: Line 1: space-separated coin values. Line 2: amount.

Output format: Number of combinations.