Sum Of List Of Lists

Write a function sum_of_list_of_lists(lol) that takes a list of lists of numbers and returns the sum of all the numbers across every inner list. An empty list of lists sums to 0.

Example

sum_of_list_of_lists([[1, 2], [3, 4]])  ->  10

Your task

Implement this function:

def sum_of_list_of_lists(lol: list):

Write the function only — the arguments are read for you and the return value is printed automatically.

Arguments arrive as one Python literal per line, in this order: lol.

Example

Input

[[1, 2], [3, 4]]

Output

10