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 No
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 No
 No

import sys
import math,bisect
from collections import defaultdict
from itertools import groupby,accumulate
from heapq import heapify,heappop,heappush
from collections import deque,Counter,OrderedDict
#input = iter(sys.stdin.buffer.read().decode().splitlines())._next_
def neo(): return map(int,input().split())
def Neo(): return list(map(int,input().split()))
n,m = neo()
A = []
for i in range(n):
    A.append(input())
f = [False for i in range(m)]
Al = set(A)
for r in Al:
    for c in range(len(r)):
        if r[c] == '#':
            if f[c]:
                print("No")
                exit()
            else:
                f[c]=True
print("Yes")
