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: Runtime Error)

/*  ex7_3
    Rikuta  */

#include <stdio.h>

int main(void)
{
    int height, width, flag;
    //与えられる行列の高さと幅の入力
    scanf("%d %d\n", &height, &width);
    char **matrix_given;
    int **on_off_matrix;

    //
    matrix_given = (char **)calloc(height+1, sizeof(char *));
    if (matrix_given==NULL)
    {
        exit(1);
    }
    for (int i = 0; i < height+1; i++)
    {
        matrix_given[i] = (char *)calloc(width, sizeof(char));
        if (matrix_given[i]==NULL)
        {
            exit(1);
        }
        
    }

    on_off_matrix = (int **)calloc(height + 1, sizeof(int *));
    if (on_off_matrix == NULL)
    {
        exit(1);
    }
    for (int i = 0; i < height + 1; i++)
    {
        on_off_matrix[i] = (int *)calloc(width, sizeof(int));
        if (on_off_matrix[i] == NULL)
        {
            exit(1);
        }
    }
    for (int i = 0; i < height; i++)
    {
        for (int j = 0; j < width + 1; j++)
        {
            //改行込みで与えられた行列を受け取る
            scanf("%c", &matrix_given[i][j]);
        }
    }
    for (int i = 0; i < height; i++)
    {
        //フラグを立てる
        flag = 1;
        for (int j = 0; j < width; j++)
        {
            if (matrix_given[i][j] == '#')
            {
                //i行について着目したときに#が一個でもあればフラグを0とする
                flag = 0;
            }
        }
        //もしi行について#がいっこもなければ
        if (flag)
        {
            for (int j = 0; j < width + 1; j++)
            {
                //on_off_matrixのi行目を1にする
                on_off_matrix[i][j] = 1;
            }
        }
    }
    for (int i = 0; i < width; i++)
    {
        //フラグを立てる
        flag = 1;
        for (int j = 0; j < height; j++)
        {
            if (matrix_given[j][i] == '#')
            {
                //i列について着目したときに#が一個でもあればフラグを0にする
                flag = 0;
            }
        }
        //i列について，#がなければ
        if (flag)
        {
            for (int j = 0; j < height; j++)
            {
                //on_off_matrixのi列目を1にする
                on_off_matrix[j][i] = 1;
            }
        }
    }

    for (int i = 0; i < height; i++)
    {
        for (int j = 0; j < width + 1; j++)
        {
            if (!on_off_matrix[i][j])
            {
                //与えられた行列の要素に対応するon_off_matrixが0ならばそれを出力する．
                printf("%c", matrix_given[i][j]);
            }
        }
    }
    
    for (int i = 0; i < height + 1; i++)
    {
        free(matrix_given[i]);
        free(on_off_matrix[i]);
    }
    free(matrix_given);
    free(on_off_matrix);

    return 0;
}