import sys, re

matrix = sys.stdin.read().splitlines()

columns_count = int(matrix[0][2])
matrix = matrix[1:]
columns = []
i=0

for _ in range(columns_count):   
    for line in matrix:
        columns.append(line[i])

    i+=1

columns = ''.join(columns)
decrypted = re.sub(r'(?<=\w)[^\w]+(?=\w)', ' ', columns)

print(decrypted)