In this task, you are given an input list A. You need to find all the elements of the list that are numbers and calculate their sum.

Q: ['3839', 'D', '4741', 'L']

A: 8580
****
Q: ['b', '5447', 'R', '8489', 'L', '627', 'P', '7491', 'c', 'c', 'r', '6923', '1167']

A: 30144
****
Q: ['1945', 'z', '8421', '2945', 'D', 't', 'm', '1747', '5815']

A:
20873
****