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)

/* ex7_3:
    Jun_JPN */

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

int main(void){

    int row_num, col_num, i, j;
    int row_flag[100] = {0}, col_flag[100] = {0};
    char **board;

    scanf("%d %d", &row_num, &col_num); // 行数，列数の順で値を取得

    /* メモリの動的確保 */
    board = (char**)malloc(sizeof(char*)*row_num);  // まず行数分(row_num個)のchar*型ポインタ配列を動的確保
    if(board == NULL){          // 動的確保できなかったらエラー表示
        fprintf(stderr, "memory allocation error.\n");
        exit(1);
    }
    for(i=0; i<row_num; i++){   // col_num個のchar型配列を各ポインタに対して動的確保
        board[i] = (char*)malloc(sizeof(char)*col_num);
        if(board[i] == NULL){   // 動的確保できなかったらエラー表示
            fprintf(stderr, "memory allocation error.\n");
            exit(1);
        }
    }

    /* 行列boardを'.'か'#'で初期化 */
    for(i=0; i<row_num; i++){           //　まずi行を固定
        for(j=0; j<col_num; j++){       // j列を動かしていく
            scanf(" %c", &board[i][j]); // (i, j)成分を入力
        }
    }

    for(i=0; i<row_num; i++){       // まずi行を固定
        for(j=0; j<col_num; j++){   // j列を動かしていく
            if(board[i][j]=='#'){   // 少なくとも１つ'#'を含む行・列に旗を立てる（＝1を代入していく）
                row_flag[i] = 1;
                col_flag[j] = 1;
            }
        }
    }

    for(i=0; i<row_num; i++){   // まずi行を固定
        if(row_flag[i]){        // 少なくとも１つ'#'がi行に含まれているとき（＝row_flag[i]に旗が立っているとき）
            for(j=0; j<col_num; j++){   // j列を動かしていく
                if(col_flag[j]){        // col_flag[j]に旗が立っているとき
                    printf("%c", board[i][j]);
                }
                if(j==col_num-1){       // i行の最後まで調べ終えたとき
                    printf("\n");
                }
            }
        }
    }

    /* メモリの解放 */
    for(i=0; i<row_num; i++){   // メモリ確保時とは逆順で
        free(board[i]);
    }
    free(board);

    return 0;
}