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import java.io.*;
import java.util.*;
/*
 * 	Heart beats fast
 * 		Colors and promises
 * 			How to be brave
 * 				How can I love when I am afraid to fall...
 */
public class Main 
{
	static final int mod=1000000007;
	static final double eps=1e-8;
	static final long inf=100000000000000000L;
	static final boolean debug=true;
	static Reader in=new Reader();
	public static void main(String[] args) throws IOException
	{
		int n=ni(),m=ni();
		String s[]=new String[n];
		for(int i=0; i<n; i++)
			s[i]=ns();
		boolean poss=true;
		for(int i=0; i<n; i++)
		{
			for(int j=0; j<i; j++)
			{
				boolean match=false;
				for(int k=0; k<m; k++)
				{
					if(s[i].charAt(k)=='#'&&s[j].charAt(k)=='#')
						match=true;
				}
				if(match)
				for(int k=0; k<m; k++)
				{
					if(s[i].charAt(k)!=s[j].charAt(k))
					{
						poss=false;
					}
				}
			}
		}
		for(int i=0; i<m; i++)
		{
			for(int j=0; j<i; j++)
			{
				boolean match=false;
				for(int k=0; k<n; k++)
				{
					if(s[k].charAt(i)=='#'&&s[k].charAt(j)=='#')
						match=true;
				}
				if(match)
				for(int k=0; k<n; k++)
				{
					if(s[k].charAt(i)!=s[k].charAt(j))
					{
						poss=false;
					}
				}
			}
		}
		
		if(poss)
			pr("Yes");
		else
			pr("No");
		System.out.println(ans);
	}
	static StringBuilder ans=new StringBuilder();
	static long powm(long a, long b, long m)
	{
		long an=1;
		long c=a;
		while(b>0)
		{
			if(b%2==1)
				an=(an*c)%m;
			c=(c*c)%m;
			b>>=1;
		}
		return an;
	}
	static Random rn=new Random();
	static void pd(){if(debug)ans.append("hola");}
	static void pd(Object a){if(debug)ans.append(a+"\n");}
	static void pr(Object a){ans.append(a+"\n");}
	static void pr(){ans.append("\n");}
	static void p(Object a){ans.append(a);}
	static int ni(){return in.nextInt();}
	static long nl(){return in.nextLong();}
	static String ns(){return in.next();}
	static double nd(){return in.nextDouble();}
	static String pr(String a, long b)
	{
		String c="";
		while(b>0)
		{
			if(b%2==1)
				c=c.concat(a);
			a=a.concat(a);
			b>>=1;
		}
		return c;
	}
	static class Reader {
        public BufferedReader reader;
        public StringTokenizer tokenizer;
        public Reader() {
            reader = new BufferedReader(new InputStreamReader(System.in), 32768);
            tokenizer = null;
        }
        public String next() {
            while (tokenizer == null || !tokenizer.hasMoreTokens()) {
                try {
                    tokenizer = new StringTokenizer(reader.readLine());
                } catch (IOException e) {
                    throw new RuntimeException(e);
                }
            }
            return tokenizer.nextToken();
        }
        public int nextInt() {
            return Integer.parseInt(next());
        }
        public long nextLong() {
        	return Long.parseLong(next());
        }
        public double nextDouble() {
        	return Double.parseDouble(next());
        }
    }
}