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
   reo012 */

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

int main(void){
    int i, j, row, column;
    char **ptr;
    int *check_row, *check_col;
    //行数と列数の入力
    scanf("%d %d\n", &row, &column);

    //ptrについて、各行の配列へのポインタ分(row行分)のメモリ確保
    ptr = (char**)calloc(row, sizeof(char*));
    if(ptr == NULL){
        exit(1);
    }
    //ptrについて、各行の要素分（column列分）のメモリ確保
    for(i=0; i<row; i++){
        ptr[i] = (char*)calloc(column, sizeof(char));
        if(ptr[i] == NULL){
            exit(1);
        }
    }

    //check_rowについて、行数分のメモリ確保
    check_row = (int*)calloc(row, sizeof(int));
    if(check_row == NULL){
        exit(1);
    }
    //check_colについて、列数分のメモリ確保
    check_col = (int*)calloc(column, sizeof(int));
    if(check_col == NULL){
        exit(1);
    }

    //グリッドを入力
    for(i=0; i<row; i++){
        for(j=0; j<column; j++){
            scanf(" %c", &ptr[i][j]);
            if(ptr[i][j]=='#'){     //黒マスのときはcheck_row,check_colに1入力
                check_row[i] = 1;
                check_col[j] = 1;
            }
        }
    }

    //i行目、j列目がともに黒マスを含む場合のみ、出力
    for(i=0; i<row; i++){
        if(check_row[i]==1){
            for(j=0; j<column; j++){
                if(check_col[j]==1){
                    printf("%c", ptr[i][j]);
                }
            }
            printf("\n");   //行ごとに改行
        }
    }

    //メモリの解放を、各行の要素分の領域、各行の配列へのポインタ分の順に解放
    for(i=0; i<row; i++){
        free(ptr[i]);
    }
    free(ptr);
    free(check_row);
    free(check_col);

    return 0;
}