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 Problem {
    public static void Main() {
        var str = "";
        while ((str = Console.ReadLine()) != "0 0") {
            var data = str.Split().Select(int.Parse).ToArray();
            var tf = "";
            var md = "";
            for (var i = 0; i < data[1]; i++) {
                tf += "#";
                md += i == 0 || i == data[1] - 1 ? "#" : ".";
            }
            Console.WriteLine(tf);
            for (var i = 1; i < data[0] - 1; i++) Console.WriteLine(md);
            Console.WriteLine(tf);
            Console.WriteLine();
        }
    }
}