using System;
using System.Collections.Generic;
using System.Linq;
using System.Numerics;
using System.Runtime.CompilerServices;


namespace ConsoleApp9
{
    class Program
    {
        static void Main(string[] args)
        {
            var size = Console.ReadLine().Split(" ", StringSplitOptions.RemoveEmptyEntries).Select(int.Parse).ToArray();

            var matrix = new string[size[0], size[1]];
            var queue = new Queue<char>();
            var wordToRemoveWhiteSpace = Console.ReadLine();
            var word = RemoveWhitespace(wordToRemoveWhiteSpace);

            // if currentRow % 2 == 0 for ++
            // else forr

            int currentRow = 0;
            int currentCol = 0;
            while (currentRow < matrix.GetLength(0))
            {
                currentCol = 0;

                if (currentRow % 2 == 0)
                {
                    for (int i = 0; i < word.Length; i++)
                    {
                        queue.Enqueue(word[i]);
                    }


                    while (currentCol < matrix.GetLength(1))
                    {
                        if (queue.Any())
                        {
                            matrix[currentRow, currentCol] = queue.Dequeue().ToString();
                            currentCol++;
                        }
                        else
                        {
                            for (int i = 0; i < word.Length; i++)
                            {
                                queue.Enqueue(word[i]);
                            }
                        }

                    }
                }
                else
                {

                    for (int j = 0; j < word.Length; j++)
                    {
                        queue.Enqueue(word[j]);
                    }

                    if (queue.Any())
                    {
                        for (int i = matrix.GetLength(1) - 1; i >= 0; i--)
                        {

                            matrix[currentRow, i] = queue.Dequeue().ToString();

                        }
                    }
                    else
                    {
                        for (int j = 0; j < word.Length; j++)
                        {
                            queue.Enqueue(word[j]);
                        }
                    }


                }

                currentRow++;
            }


            for (int row = 0; row < matrix.GetLength(0); row++)
            {
                for (int col = 0; col < matrix.GetLength(1); col++)
                {
                    Console.Write(matrix[row, col]);
                }

                Console.WriteLine();
            }

        }

        public static string RemoveWhitespace(string input)
        {
            return new string(input.ToCharArray()
                .Where(c => !Char.IsWhiteSpace(c))
                .ToArray());

        }
    }
}