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.Scanner;
public class Main {
	public static void main(String[] args) {
		StringBuilder sb=new StringBuilder("");
		Scanner n=new Scanner(System.in);
		int a=n.nextInt();
		int b=n.nextInt();
		while (a!=0 || b!=0){
			for (int c=0;c<b;c++){
					sb.append("#");
			}
			System.out.println(sb);
			sb.append("\n");//改行
			sb=new StringBuilder("#");
			for (int d=2;d<a;d++){
				for (int e=2;e<b;e++){
					sb.append(".");
				}
				sb.append("#");
				System.out.println(sb);
				sb.append("\n");//改行
				sb=new StringBuilder("#");
			}
			for (int c=1;c<b;c++){
				sb.append("#");
			}
		sb.append("\n");//改行
		System.out.println(sb);
		a=n.nextInt();b=n.nextInt();
		sb=new StringBuilder("");
		}
	}
}