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: ['k', '1489', 'x', '6543', 'I', 'l', 'D', '6299', '1473', 'a', '7661', 'z', 'E', 'Z', 'U', '3671', '2873', 'e', 'p']
Example Output: 30009

Example Input: ['Q', 'v', 't', '223', 'm', 'l', 'c', 'M', 'b', '2227', 'P', 'e', 'n', 'f', 'S', '2205', '3517', '5545']
Example Output:
13717