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.Collections.Generic;
using System.Linq;
using System.Text;
using System.Collections;

namespace ConsoleApp9
{   
    class Program
    {
        public static void Main(string[] args) {
            while (true)
            {
                string[] sss = Console.ReadLine().Split(' ');
                int a = int.Parse(sss[0]); int b = int.Parse(sss[1]);
                if (a == 0 && b == 0) { break; }
                for (int c = 1; c <= a; c++)
                {
                    for (int d = 1; d <= b; d++)
                    {
                        if (c == 1 || c == a || d == 1 || d == b)
                        {
                            Console.Write("#");
                        }
                        else { Console.Write("."); }
                    }
                    Console.WriteLine();
                }
                Console.WriteLine();
            }
        }
    }
}