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.

Q: ['Y', '9053', 'N', '6921']

A: 15974
****
Q: ['1203', '6179', '9835']

A: 17217
****
Q: ['4537', '7019', 'Z', '6625', '2015']

A:
20196
****