Problem:
Score : 200 points

Problem Statement

There is a grid of squares with H horizontal rows and W vertical columns.
The square at the i-th row from the top and the j-th column from the left is represented as (i, j).
Each square is black or white.
The color of the square is given as an H-by-W matrix (a_{i, j}).
If a_{i, j} is ., the square (i, j) is white; if a_{i, j} is #, the square (i, j) is black.

Snuke is compressing this grid.
He will do so by repeatedly performing the following operation while there is a row or column that consists only of white squares:

Operation: choose any one row or column that consists only of white squares, remove it and delete the space between the rows or columns.

It can be shown that the final state of the grid is uniquely determined regardless of what row or column is chosen in each operation.
Find the final state of the grid.

Constraints

1 \leq H, W \leq 100

a_{i, j} is . or #.

There is at least one black square in the whole grid.

Input

Input is given from Standard Input in the following format:

H W
a_{1, 1}...a_{1, W}
:
a_{H, 1}...a_{H, W}

Output

Print the final state of the grid in the same format as input (without the numbers of rows and columns); see the samples for clarity.

Sample Input 1

4 4
##.#
....
##.#
.#.#

Sample Output 1

###
###
.##

The second row and the third column in the original grid will be removed.

Sample Input 2

3 3
#..
.#.
..#

Sample Output 2

#..
.#.
..#

As there is no row or column that consists only of white squares, no operation will be performed.

Sample Input 3

4 5
.....
.....
..#..
.....

Sample Output 3

#

Sample Input 4

7 6
......
....#.
.#....
..#...
..#...
......
.#..#.

Sample Output 4

..#
#..
.#.
.#.
#.#

Solution in C# (Mono 4.6.2.0) (judge verdict: Wrong Answer)

using System;
using System.Collections.Generic;
using System.Linq;
using static Atcoder;
using System.Threading.Tasks;
using System.ComponentModel;

public class Hello
{

    public static void Main()
    {
        int[] n = SpIntRead(' ');
        int H = n[0];
        int W = n[1];
        string[] s = new string[H];
        bool[] h = new bool[H];
        bool[] w = new bool[W];
        for (int i = 0; i < H; i++) s[i] = Console.ReadLine();
        for (int i = 0; i < H; i++)
        {
            if (s[i].Count(c => c == s[i][0]) == W) h[i] = false;
            else h[i] = true;
        }
        bool f = false;
        for (int i = 0; i < W; i++)
        {
            for (int j = 0; j < H; j++)
            {
                if (s[0][i] == s[j][i]) f = true;
                else { f = false; break; }
            }
            if (f) w[i] = false;
            else w[i] = true;
        }
        bool write = false;
        for (int i = 0; i < H; i++) {
            if (!h[i]) continue;
            write = false;
            for (int j = 0; j < W; j++) {
                if (h[i] && w[j]) { Console.Write(s[i][j]); write = true; }
            }
            if (write) Console.WriteLine();
        }
    }
}


public class Atcoder
{
    static void Swap<T>(ref T a, ref T b)
    {
        var t = a;
        a = b;
        b = t;
    }
    public static long LCM(long a, long b)
    {
        long c = a * b;
        if (a < b) Swap(ref a, ref b);
        long d = a % b;
        while (d != 0)
        {
            a = b;
            b = d;
            d = a % b;
        }
        return c / b;
    }
    public static string strReverce(string s)
    {
        return new string(s.Reverse().ToArray());
    }
    public static int intRead()
    {
        return int.Parse(Console.ReadLine());
    }
    public static bool IsPrime(int n)
    {
        if (n < 2) return false;
        if (n == 2) return true;
        if (n % 2 == 0) return false;

        //double sqrtNum = Math.Sqrt(n);
        for (int i = 3; i < n; i += 2)
        {
            if (n % i == 0) return false;
        }
        return true;
    }
    public static string[] SpRead(char c)
    {
        return Console.ReadLine().Split(c);
    }
    public static int[] SpIntRead(char c)
    {
        return Console.ReadLine().Split(' ').Select(a => int.Parse(a)).ToArray();
    }
    public static string ToConvertBit(int N, int e)
    {
        string ret = "";
        int r = 0;
        while (N != 0)
        {
            r = N % e;
            ret += r.ToString();
            N -= r;
            N /= e;
        }
        ret = strReverce(ret);
        return ret;
    }

}