07. Snake - Moves Multidimensional Lists - Exercise 1

#  07. Snake Moves

# Multidimensional Lists - Exercise 1
#  https://judge.softuni.org/Contests/Practice/Index/1835#6


from collections import deque

size = input().split()
n = int(size[0])
m = int(size[1])

word = input()
snake = deque(word)
matrix = []

for row in range(n):
    matrix.append([])
    for col in range(m):
        letter_to_add = snake.popleft()
        matrix[row].append(letter_to_add)
        if not snake:
            snake = deque(word)

counter = 0
for sub_matrix in matrix:
    if counter % 2 == 0:
        print(''.join(sub_matrix))
    else:
        print(''.join(sub_matrix[::-1]))

    counter += 1