using System;
using System.Collections.Generic;
using System.Linq;

namespace _5._Snake_Moves
{
    class StartUp
    {
        static void Main(string[] args)
        {
            var dimensions = Console.ReadLine().Split(" ", StringSplitOptions.RemoveEmptyEntries).Select(int.Parse).ToArray();

            int rows = dimensions[0];
            int cols = dimensions[1];
            var matrix = new char[rows, cols];

            string snake = Console.ReadLine();
            int index = 0;
            for (int row = 0; row < rows; row++)
            {
                var curRow = new List<char>();
                while(curRow.Count <= rows)
                {
                    curRow.Add(snake[index]);
                    index++;
                    if (index > cols)
                    {
                        index = 0;
                    }
                }
                if (row % 2 == 1)
                {
                    curRow.Reverse();
                }
                for (int col = 0; col < cols; col++)
                {
                    matrix[row, col] = curRow[col];
                }
            }

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

        }
    }
}