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 flame{
    public static void Main(){
        while(true){
            String[] str = Console.ReadLine().Split(' ');
            int a = int.Parse(str[0]);
            int b = int.Parse(str[1]);
            if(a+b==0){
                break;
            }
            else{
                for(int i=0; i<a; i++){
                    for(int j=0; j<b; j++){
                        if(i==0 || i==a-1 || j==0 || j==b-1){
                            Console.Write("#");
                        }
                        else{
                            Console.Write(".");
                        }
                    }
                    Console.WriteLine("");
                }
            }
            Console.WriteLine("");
        }
    }
}