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.

['2087', '8171', 'c', 'd', 'a', '5621', 'n']
15879

['k', '4991', '7289', '4355', 'I', '8415', '5175', '5329', 'G', 'a', '7193', 't', '8821', 'j', '7239', '405', 'y', 'O', '9881', 'w']
69093

['8259', 'F', '4451', '7309', '625', '6263', 'k', '1497', 'R', 'T', 'm', '621', 'z', 'N', 't', '6579']

35604