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# inp.readline()
# int(inp.readline())
# out.write()
# raw_input()
# map(int,raw_input().split())
# map(int,inp.readline().split())
def main():
    an=""
    n,m=map(int,inp.readline().split())
    a=[0]*n
    for i in xrange(n):
        a[i]=(inp.readline().strip())
    d={}
    for i in xrange(n):
        try:
            d[a[i]].append(i)
        except KeyError:
            d[a[i]]=[i]
    z=0
    for i in d:
        d[i]=set(d[i])
    t=set([i for i in xrange(n)])
    for i in d:
        q=t.difference(d[i])
        r=[]
        for j in xrange(m):
            if i[j]=='#':
                r.append(j)
        for j in r:
            for k in q:
                if a[k][j]=='#':
                    print "No"
                    exit(0)
    print "Yes"
    out.write(an)
if __name__ == "__main__":
    from sys import stdin as inp, stdout as out
    main()