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;

class ITP1
{
    static void Main()
    {
        for (; ; )
        {
        var a = Console.ReadLine();
        int b = int.Parse(a.Split(' ')[0]);
        int c = int.Parse(a.Split(' ')[1]);
            if (b == 0 && c == 0) { break; }
            for (int i = 0; i < b; i++)
            {
                for (int j = 0; j < c; j++)
                {
                    if (i == 0 || i == b - 1 || j == 0 || j == c - 1)
                    {
                        Console.Write('#');
                    }
                    else
                    {
                        Console.Write('.');
                    }
                }
                Console.Write('\n');
            }
            Console.Write('\n');
        }
    }
}