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 No

#!/usr/bin/env python3

import sys

[n, m] = map(int, sys.stdin.readline().strip().split())
table = [sys.stdin.readline().strip() for _ in range(n)]

first_to_row = dict()

poss = True
for row in table:
	first = row.find('#')
	if first in first_to_row:
		if first_to_row[first] != row:
			poss = False
			break
	else:
		first_to_row[first] = row


if poss:
	counts = [False for _ in range(m)]
	for row in first_to_row.values():
		for i in range(m):
			if row[i] == '#':
				if counts[i]:
					poss = False
					break
				counts[i] = True
		if not poss:
			break


if poss:
	print ('Yes')
else:
	print ('No')
