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 Program
{
    static void Main()
    {
        
        while(true){
            var nums = Console.ReadLine().Split(' ').Select(s => int.Parse(s)).ToArray();
            int vertical = nums[0];
            int side = nums[1];
            
            if(vertical==0 && side==0){
                break;
            }
            
            for(int i = 0; i < vertical; i++){
                for(int l = 0; l < side; l++){
                    
                    if(i == 0 || i == (vertical - 1)){
                        Console.Write("#");
                    }else if(l == 0 || l == (side - 1)){
                        Console.Write("#");
                    }else{
                        Console.Write(".");
                    }
                    
                }
                
                Console.WriteLine();
            
                
            }
            Console.WriteLine();
        }
    }
}