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;
public class Hello{
    public static void Main(){
        bool isCon = true;
        while(isCon){
            string tmp = System.Console.ReadLine();
            string[] ab = tmp.Split(' ');
            int a = Convert.ToInt32(ab[0]);
            int b = Convert.ToInt32(ab[1]);
            
            if(a == 0 && b == 0){
                isCon = false;
            }else{
                for(int i = 0; i<a;i++){
                    for(int j = 0; j < b; j++){
                        if(0<i && i<a-1 && 0<j && j<b-1){
                            Console.Write(".");
                        }else{
                            Console.Write("#");
                        }
                    }
                    Console.WriteLine();
                }
                Console.WriteLine();
                
            }
        }
    }
}