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;
using System.Text;

// フレームの描画

public class ITP1_5_B
{
    public static void Main(string[] args)
    {
        //var exStdIn = new System.IO.StreamReader( "input.txt" );
        //System.Console.SetIn( exStdIn );

        StringBuilder sb = new StringBuilder();
        while (true)
        {
            int[] nums = Console.ReadLine().Split(' ').Select(x => int.Parse(x)).ToArray();
            int h = nums[0];
            int w = nums[1];
            if (h == 0 && w == 0)
            {
                break;
            }
            for (int i = 0; i < h; i++)
            {
                for (int j = 0; j < w; j++)
                {
                    if (i == 0 || i == h - 1 || j == 0 || j == w - 1)
                    {
                        sb.Append("#");
                    }
                    else
                    {
                        sb.Append(".");
                    }
                }
                sb.AppendLine();
            }
            sb.AppendLine();
        }
        Console.Write(sb.ToString());
    }
}