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 LIB;
using System;
using System.Linq;
using System.Text;
using System.Collections.Generic;

class Program
{
    static void Main(string[] args)
    {
        while (true)
        {
            int[] n = io.r<int>(' ');
            if (n[0] == n[1] && n[0] == 0) { break; }
            for (int i = 0; i < n[0]; i++)
            {
                for (int j = 0; j < n[1]; j++)
                {
                    if (i == 0 || i == n[0] - 1 || j == 0 || j == n[1] - 1)
                    {
                        io.w("#", false);
                    }
                    else
                    {
                        io.w(".", false);
                    }
                }
                io.w("");
            }
            io.w("");
        }
        io.wflush();
    }
}

namespace LIB
{
    public class io
    {
        private const int WMAX = 1000;
        private static StringBuilder S = new StringBuilder();
        public static T r<T>() { return util.parse<T>(r()); }
        public static T[] r<T>(char s = ' ') { return r().Split(s).Select(util.parse<T>).ToArray(); }
        public static T[] r<T>(int l) { T[] r = new T[l]; for (int i = 0; i < l; i++) { r[i] = r<T>(); } return r; }
        public static T[][] r<T>(int l, char s = ' ') { T[][] r = new T[l][]; for (int i = 0; i < l; i++) { r[i] = r<T>(s); } return r; }
        private static string r() { return Console.ReadLine(); }
        public static void w(object v, bool lf = true) { S.Append(util.parse<string>(v)); if (lf == true) { S.Append('\n'); } if (S.Length >= WMAX) { wflush(); } }
        public static void wflush() { Console.Write(S.ToString()); S.Length = 0; }
    }
    public class util
    {
        public static T parse<T>(object value) { return (T)(Convert.ChangeType(value, typeof(T))); }
    }
    public class memo<Key, Result>
    {
        private Dictionary<Key, Result> R;
        public memo() { R = new Dictionary<Key, Result>(); }
        public Result exec(Key k, Func<Key, Result> f) { Result r; if (R.ContainsKey(k)) { r = R[k]; } else { r = f(k); R.Add(k, r); } return r; }
    }
}