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: ['8739', 'K']

Answer: 8739


Question: ['3433', '6955', 'Q', 'E', '3557', 'S', '2931', '9879', 'S', 'f', 'Q']

Answer: 26755


Question: ['6367', '9923', '9141']

Answer:
25431