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import sys

n, m = map(int, input().split())

sys.setrecursionlimit(10000)

grid = [[i for i in input()] for _ in range(n)]
# print(*grid, sep='\n')

visited_cells = [[False] * m for _ in range(n)]


def correct_grid(row, column, parent_row, parent_column):
    visited_cells[row][column] = True
    # print(*visited_cells, sep='\n')
    visited_rows[row] = True
    visited_columns[column] = True
    if row + 1 < n and (row + 1 != parent_row or column != parent_column):
        down = row + 1
        while down < n:
            if grid[down][column] == '.' and visited_rows[down]:
                print('No')
                sys.exit()
            elif grid[down][column] == '.':
                down += 1
            elif grid[down][column] == '#' and not visited_cells[down][column]:
                correct_grid(down, column, down - 1, column)
                break
            else:
                break
    if row - 1 > -1 and (row - 1 != parent_row or column != parent_column):
        up = row - 1
        while up > -1:
            if grid[up][column] == '.' and visited_rows[up]:
                print('No')
                sys.exit()
            elif grid[up][column] == '.':
                up -= 1
            elif grid[up][column] == '#' and not visited_cells[up][column]:
                correct_grid(up, column, up + 1, column)
                break
            else:
                break
    # print('Here')
    if column + 1 < m and (row != parent_row or column + 1 != parent_column):
        right = column + 1
        while right < m:
            if grid[row][right] == '.' and visited_columns[right]:
                print('No')
                sys.exit()
            elif grid[row][right] == '.':
                right += 1
            elif grid[row][right] == '#' and not visited_cells[row][right]:
                correct_grid(row, right, row, right - 1)
                break
            else:
                break
    # print('And here')
    if column - 1 > -1 and (row != parent_row or column - 1 != parent_column):
        left = column - 1
        while left > -1:
            if grid[row][left] == '.' and visited_columns[left]:
                print('No')
                sys.exit()
            elif grid[row][left] == '.':
                left -= 1
            elif grid[row][left] == '#' and not visited_cells[row][left]:
                correct_grid(row, left, row, left + 1)
                break
            else:
                break


for r in range(n):
    for col in range(m):
        if grid[r][col] == '#':
            visited_rows = [False] * n
            visited_columns = [False] * m
            correct_grid(r, col, r, col)

print('Yes')


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