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)
s = ''.join(matrix[y][x] for x in range(m) for y in range(n))
p = r'(?<=[a-zA-Z0-9])[!@#$%&\s]+(?=[a-zA-Z0-9])'
print(re.sub(p, ' ', s))