# -*- coding:utf-8 -*-
# class ListNode:
#     def __init__(self, x):
#         self.val = x
#         self.next = None
class Solution:
    # 返回合并后列表
    def Merge(self, pHead1, pHead2):
        # write code here
        root=ListNode(None)
        head=root
        node1=pHead1
        node2=pHead2
        if node1 and not node2 : return node1
        elif not node1 and node2 : return node2
        elif not node1 and not node2: return None
        while node1 and node2:
            if node1.val<=node2.val:
                root.next=node1
                node1=node1.next
                root=root.next
            else:
                root.next=node2
                node2=node2.next
                root=root.next
            if not node1:
                root.next=node2
            elif not node2:
                root.next=node1
        return head.next