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;

public class Sample18{
    public static void Main(){
        while (true){
            string[] line = Console.ReadLine().Trim().Split(' ');
            if ((line[0] == "0") && (line[1]=="0")){
                break;
            }
            var h = int.Parse(line[0]);
            var w = int.Parse(line[1]);
            var s1 = "";
            var s2 = "";
            for (int i = 0; i < w; i++) s1 += "#";
            for (int i = 0; i < w-2; i++) s2 += ".";
            s2 = "#" + s2 + "#";
            Console.WriteLine(s1);
            for (int i = 0; i < h - 2;  i++)
                Console.WriteLine(s2);
            Console.WriteLine(s1);
            Console.WriteLine();
        }
    }
}