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 Lua (Lua 5.3.5) (judge verdict: Accepted)

local read = io.read
local concat = table.concat
local char = string.char

local h, w = read("n", "n", "l")
local black = string.byte("#")

local a_t = {}
for i = 1, h do
	a_t[i] = read()
end

local del_i_t = {}
for i = 1, h do
	local is_breaked = false
	for j = 1, w do
		if a_t[i]:byte(j) == black then
			is_breaked = true
			break
		end
	end
	if not is_breaked then
		del_i_t[i] = true
	end
end

local del_j_t = {}
for j = 1, w do
	local is_breaked = false
	for i = 1, h do
		if a_t[i]:byte(j) == black then
			is_breaked = true
			break
		end
	end
	if not is_breaked then
		del_j_t[j] = true
	end
end

local copy_a_t = {}
local last_i = 0
for i = 1, h do
	if not del_i_t[i] then
		last_i = last_i + 1
		local last_j = 0
		copy_a_t[last_i] = {}
		for j = 1, w do
			if not del_j_t[j] then
				last_j = last_j + 1
				copy_a_t[last_i][last_j] = a_t[i]:sub(j, j) --char(a_t[i]:byte(j))
			end
		end
	end
end

local out_t = {}
for i = 1, #copy_a_t do
	out_t[i] = concat(copy_a_t[i], "")
end

print(concat(out_t, "\n"))