here is my solution icomplie in python 3

!/bin/python3

import re

first_multiple_input = input().rstrip().split()

n = int(first_multiple_input[0]) m = int(first_multiple_input[1])

matrix = []

for _ in range(n): matrix_item = input() matrix.append(matrix_item.ljust(m))

string = ''.join(matrix[row][col] for col in range(m) for row in range(n))

output = re.sub(r'(?<=\w)[!@#$&% ]+(?=\w)', ' ', string)

print(output)