Problem:
Print a Frame

Draw a frame which has a height of H cm and a width of W cm. For example, the following figure shows a frame which has a height of 6 cm and a width of 10 cm.

##########
#........#
#........#
#........#
#........#
##########

Input

The input consists of multiple datasets. Each dataset consists of two integers H and W separated by a single space.

The input ends with two 0 (when both H and W are zero).

Output

For each dataset, print the frame made of '#' and '.'.

Print a blank line after each dataset.

Constraints

3 ≤ H ≤ 300

3 ≤ W ≤ 300

Sample Input

3 4
5 6
3 3
0 0

Sample Output

####
#..#
####

######
#....#
#....#
#....#
######

###
#.#
###

Solution in C# (judge verdict: Accepted)

using System;

namespace Test
{
    class MainClass
    {
        public static void Main(string[] args)
        {
            while (true)
            {
                var inputs = Console.ReadLine().Split(' ');
                var nums = Array.ConvertAll(inputs, int.Parse);
                if ((nums[0] | nums[1]) == 0) return;
                var H = nums[0];
                var W = nums[1];
                const char outsideBlock = '#';
                const char insideBlock = '.';
                var frame = new char[H,W];

                for (int h = 0; h < H; h++)
                {
                    for (int w = 0; w < W; w++)
                    {
                        if (h == 0 || h == H - 1 || w == 0 || w == W - 1)
                        {
                            frame[h,w] = outsideBlock;
                        }
                        else
                        {
                            frame[h,w] = insideBlock;
                        }
                    }
                }

                for (int h = 0; h < H; h++)
                {
                    for (int w = 0; w < W; w++)
                    {
                        Console.Write(frame[h,w]);
                    }
                    Console.WriteLine();
                }
                Console.WriteLine();
            }
        }
    }
}