You are given two linked lists: list1 and list2 of sizes n and m respectively. Remove list1's nodes from the ath node to the bth node, and put list2 in their place. The blue edges and nodes in the following figure incidate the result: Build the result list and return its head. Example 1: Input: list1 = [0,1,2,3,4,5], a = 3, b = 4, list2 = [1000000,1000001,1000002] Output: [0,1,2,1000000,1000001,1000002,5] Explanation: We remove the nodes 3 and 4 and put the entire list2 in their place. The blue edges and nodes in the above figure indicate the result. Example 2: Input: list1 = [0,1,2,3,4,5,6], a = 2, b = 5, list2 = [1000000,1000001,1000002,1000003,1000004] Output: [0,1,1000000,1000001,1000002,1000003,1000004,6] Explanation: The blue edges and nodes in the above figure indicate the result. Constraints: 3 <= list1.length <= 104 1 <= a <= b < list1.length - 1 1 <= list2.length <= 104