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 Scala (judge verdict: Accepted)

import scala.io.StdIn

object Main {
  def main(args: Array[String]): Unit = {
    val inputs = Iterator.continually(StdIn.readLine()).takeWhile(_ != null)
    for{
      in <- inputs
      val Array(h, w, _*) = in.split(" ").map(_.toInt)
      }{
        if(h != 0 && w != 0){
          println((List.tabulate(h,  w){(i,  j) =>
            if(j == w-1) "#\n"
            else if(i == 0 || i == h-1 || j == 0 || j == w-1) "#"
            else "."
          }).flatten.mkString)
        }
      }
  }
}