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 Program {
    static void Main( string[] args )
    {
        while ( true ) {
            string[] input = Console.ReadLine().Split();

            int h = int.Parse( input[ 0 ] );
            int w = int.Parse( input[ 1 ] );

            if ( 0 == h + w ) {
                break;
            }

            string b = new string( '#', w );

            if ( h > 0 && h < 3 ) {
                for ( int i = 0; i < h; ++i ) {
                    Console.WriteLine( b );
                }

            } else if ( h > 2 ) {
                string m;

                if ( w > 0 && w < 3 ) {
                    m = b;

                } else if ( w > 2 ) {
                    m = string.Concat( '#', new string( '.', w - 2 ), '#' );

                } else {
                    continue;
                }

                Console.WriteLine( b );

                for ( int i = 0; i < h - 2; ++i ) {
                    Console.WriteLine( m );
                }

                Console.WriteLine( b );

            } else {
                continue;
            }

            Console.WriteLine();
        }
    }
}