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.

['P', '6299', '9655', 'l', '6317', '2139', '3347', 'l', '3095', '7363', '3115', '7529', 'R']
48859

['r', '6537', '3001', '7879']
17417

['5681', '2541', '6169', '5689', 'i', 'M']

20080