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;
using System.Linq;

namespace AOJ_Practice
{
    class Program
    {
        static void Main(string[] args)
        {
            while (true)
            {
                var inputs = Console.ReadLine().Split(' ').Select(int.Parse).ToList();

                if (inputs.All(x => x == 0))
                {
                    goto Finish;
                }

                var height = inputs[0];
                var width = inputs[1];

                for (int i = 0; i < height; i++)
                {
                    if (i == 0 || i + 1 == height)
                    {
                        for (int j = 0; j < width; j++)
                        {
                            Console.Write("#");
                        }
                    }
                    else
                    {
                        Console.Write($"#{new string('.',width-2)}#");
                    }

                    Console.WriteLine();
                }

                Console.WriteLine();
            }

            Finish:
            return;
        }
    }
}