TASK DEFINITION: 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.
PROBLEM: ['r', '3537', 'T', '3611', 'k', '4983', 'h', '4317', '8727', 'E', '6471', '8465', 'f', '5429', 'T', '2169', '2171', 'P', '6941', 'D']

SOLUTION: 56821

PROBLEM: ['6577', 'Q', '6865', '7671', 'N']

SOLUTION: 21113

PROBLEM: ['7847', 'I', 'Z', '4811', '623', '6397', '8271', '4187', 'R', '9597', 'H', 'u', 'e', '527', '3761', 'b', '4509', 'm']

SOLUTION:
50530