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 JAVA (judge verdict: Accepted)

import java.util.*;
import java.lang.*;
import java.io.*;

class Main
{
	public static void main (String[] args) throws java.lang.Exception
	{
		String u, nl = System.getProperty("line.separator");
		StringBuilder 
			p = new StringBuilder(1000),
		  	d = (new StringBuilder(100)).append("."),
		  	s = (new StringBuilder(100)).append("#"),
		  	k = new StringBuilder(100);
		Scanner r = new Scanner(System.in);
		int h, w, ww = 0x10;
		while (0 != (ww >>= 1)) {
			d.append(d);
			s.append(s);
		}
		ww = d.length();
		while (0 != ((h = r.nextInt()) | (w = r.nextInt()))) {
			while (w > ww) {
				d.append(d);
				s.append(s);
				ww = d.length();
			}
			p.append(u = s.substring(0, w)).append(nl);
			k.setLength(0);
			k.append(d.substring(0, w)).append(nl)
			.replace(0, 1, "#").replace(w - 1, w, "#");
			while (2 != h--) {
				p.append(k);
			}
			p.append(u).append(nl).append(nl);
		}
		System.out.print(p);
	}
}