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.IO;

namespace Ex160506_1{
    public class Program{
        public static void Main(string[] args){
            var sw = new StreamWriter(Console.OpenStandardOutput()){AutoFlush = false};

            while(true){
                var input = Console.ReadLine().Split(' ');
                var h = int.Parse(input[0]);
                var w = int.Parse(input[1]);

                if(h == 0) break;
                for(var i = 1; i <= h; i++){
                    for(var j = 1; j <= w; j++){
                        if(i == 1 || i == h || j == 1 || j == w){
                            sw.Write('#');
                        } else{
                            sw.Write('.');
                        }
                    }
                    sw.WriteLine();
                }
                sw.WriteLine();
            }
            sw.Flush();
        }
    }
}