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: ['R', 'I', 'f', 'K', 'p', '8579', 'e', '1223', 'I', 'K', '8311', '2147', '4241', 'z', '6671', 'r']
Example Output: 31172

Example Input: ['a', 'm', '3205', '1869', '1117', 'K', '5785']
Example Output: 11976

Example Input: ['S', '8851', 'H', '6847', '8199', '7179', '7243', '5305', 'u', 'z', 'I', '79', '6319', '245', '4525', 'N', 'Q']
Example Output:
54792