Merge Sorted Lists

You are given a list of lists, and each inner list is already sorted in increasing order. Return one list with all the numbers, sorted in increasing order.

Examples

Example 1

Input:

merge_sorted_lists([[1, 4, 7], [2, 5], [3, 6, 9]])

Output:

[1, 2, 3, 4, 5, 6, 7, 9]

Example 2

Input:

merge_sorted_lists([[], [1], []])

Output:

[1]

Constraints

• 0 <= len(lists) <= 100
• The total number of values is at most 5 * 10**5.
• Inner lists can be empty.