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;
class Program
{
    static void Main(string[] args)
    {
        while (true)
        {
            string[] data = Console.ReadLine().Split(' ');
            int H = int.Parse(data[0]);
            int W = int.Parse(data[1]);
            if (H == 0 && W == 0)
            {
                return;
            }

            string line = "";
            string line2 = "";
            for (int i = 0,count = W -1; i < W; i++)
            {
                line = line + "#";
                if (i == 0 || i == count)
                {
                    line2 = line2 + "#";
                }
                else
                {
                    line2 = line2 + ".";
                }
            }

            for (int i = 0,count = H - 1; i < H; i++)
            {
                if (i == 0 || i == count)
                {
                    Console.WriteLine(line);
                }
                else
                {
                    Console.WriteLine(line2);
                }
            }
            Console.WriteLine();
        }
    }
}