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.

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

Example Input: ['3319', 'e', 'c', 'G', '2399', '1557', '4813', 'z', 'U', '4895', 's', '1193', 'A', 'G']
Example Output: 18176

Example Input: ['5967', 'c', 'k', '2243', 'v', 'Z', '5379', '7705', 'n', '2151', 'U', '4805', '6179', 'd', 'A', 'u', '8419', '9799', 'k']
Example Output:
52647