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.
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Question: ['x', '9895', 'r', 'H', 'C']

Answer: 9895


Question: ['2683', '4431']

Answer: 7114


Question: ['h', '833', '1689', 'X', 'S', 'U', '3215', '4173', 'L', 'P', 'D', '5659']

Answer:
15569