Shashank is very excited after learning about the linked list. He learned about how to merge two linked lists. When we merge two linked lists, the order of the elements of each list doesn't change. For example, if we merge and , is a valid merge, while is not a valid merge because appears before .

Shashank wants you to solve a problem for him: You are given two lists having sizes and . How many ways can we merge both the lists? It is given that all elements are distinct. As your answer can be quite large, Shashank wants you to print it .