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 AOJ {
    static void Main(string[] args)
    {
        string[] s;

        while ((s = Console.ReadLine().Split(' ')) != null) {

        int H = int.Parse(s[0]);
        int W = int.Parse(s[1]);

        if (H == 0 && W == 0) break;

        string side = "";
        string mid = "";

        for (int i = 0; i < W; i++) {

            side += "#";

            if (i == 0 || i == W-1)
                mid += "#";

            else
                mid += ".";
        }

        for (int i = 0; i < H; i++) {

            if (i == 0 || i == H-1)
                Console.WriteLine(side);

            else
                Console.WriteLine(mid);
        }
        Console.WriteLine();
        }
    }
}