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 (GCC 9.2.1) (judge verdict: Accepted)

/* ex 7_3
   kanon */

#include <stdio.h>
#include <stdlib.h>

int main(void)
{
    //与えられる値を入れる数を宣言
    int i, j, height, width, *row_bool, *column_bool, flag = 0;
    char **ptr;

    //変数に値を入力する
    scanf("%d %d", &height, &width);

    //行と列のbool配列を作りメモリの動的確保
    row_bool = (int *)calloc(height, sizeof(int));
    if (row_bool == NULL)
    {
        fprintf(stderr, "calloc error.\n");
        exit(1);
    }

    column_bool = (int *)calloc(width, sizeof(int));
    if (column_bool == NULL)
    {
        fprintf(stderr, "calloc error.\n");
        exit(1);
    }

    //各行の配列へのポインタ分のメモリ領域を確保
    ptr = (char **)calloc(height, sizeof(char *));
    if (ptr == NULL)
    {
        fprintf(stderr, "calloc error.\n");
        exit(1);
    }

    //ptrの各行の要素分のメモリ領域を確保
    for (i = 0; i < height; i++)
    {
        ptr[i] = (char *)calloc(width, sizeof(char));
        if (ptr[i] == NULL)
        {
            fprintf(stderr, "calloc error.\n");
            exit(1);
        }
    }

    for (i = 0; i < height; i++)
    {
        scanf("%s", ptr[i]);
    }

    //行と列のbool配列の要素を１に揃える
    for (i = 0; i < height; i++)
        row_bool[i] = 1;
    for (i = 0; i < width; i++)
        column_bool[i] = 1;

    //完全に.のみの行と列を見つける
    for (i = 0; i < height; i++)
    {
        flag = 1;
        for (j = 0; j < width; j++)
        {
            if (ptr[i][j] != '.')
                flag = 0;
        }
        //完全に.のみの行はfalseに変える
        if (flag)
            row_bool[i] = 0;
    }

    for (i = 0; i < width; i++)
    {
        flag = 1;
        for (j = 0; j < height; j++)
        {
            if (ptr[j][i] != '.')
                flag = 0;
        }
        //完全に.のみの列はfalseに変える
        if (flag)
            column_bool[i] = 0;
    }

    //答えを出力
    for (i = 0; i < height; i++)
    {
        if (row_bool[i])
        {
            for (j = 0; j < width; j++)
            {
                if (column_bool[j])
                {
                    printf("%c", ptr[i][j]);
                }
            }
            printf("\n");
        }
    }

    //メモリ領域の解放，各行の要素分の領域を開放し，
    //各行の配列へのポインタの領域を解放
    //（メモリ領域の確保と逆順）
    for (i = 0; i < height; i++)
    {
        free(ptr[i]);
    }
    free(ptr);
    free(row_bool);
    free(column_bool);

    return 0;
}