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: ['1391', '1719', '8547', 'x', 'a', 'j', '6395', 't', '3421', '6607', 'M', '1645', 'H', 'x', 't']

Answer: 29725


Question: ['t', '7469', 'Y', 'N', '8137']

Answer: 15606


Question: ['U', '6885', 'o', 's', '5425', '7023', '1835', '6141', '3829']

Answer:
31138