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 ConsoleApplication3
{
    class Program
    {
        static void Main(string[] args)
        {
            int a, b;
            while (true)
            {
                string[] array = Console.ReadLine().Split(' ');
                a = int.Parse(array[0]);
                b = int.Parse(array[1]);
                if (a == 0 && b == 0)
                {
                    break;
                }
                for (int i = 0; i < a; i++)
                {
                    if (i == 0 || i + 1 == a)
                    {
                        string output = new string('#', b);
                        Console.WriteLine(output);
                    }
                    else
                    {
                        string inner = new string('.', b - 2);
                        Console.WriteLine('#' + inner + '#');
                    }
                }
                Console.WriteLine("");
            }
        }
    }
}