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import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.util.StringTokenizer;

public class B {
public static boolean identical(char []a,char []b)
{
	int n=a.length;
	for(int i=0;i<n;i++)
		if(a[i]!=b[i])
			return false;
	return true;
}
	public static void main(String[] args) throws IOException {
		Scanner sc=new Scanner(System.in);
		PrintWriter pw=new PrintWriter(System.out);
		int n=sc.nextInt(),m=sc.nextInt();
		char[][]s=new char [n][m];
		for(int i=0;i<n;i++)
			s[i]=sc.nextLine().toCharArray();
		for(int i=0;i<n;i++)
			for(int j=0;j<m;j++)
			{
				if(s[i][j]=='.')
					continue;
				for(int k=i+1;k<n;k++)
					if(s[k][j]=='#')
					{
						if(!identical(s[i],s[k]))
						{
							System.out.println("No");
							return;
						}
					}
			}
		
		System.out.println("Yes");
		pw.close();

	}
	static class Scanner
	{
		BufferedReader br;
		StringTokenizer st;
		public Scanner(InputStream s)
		{
			br=new BufferedReader(new InputStreamReader(s));
		}
		public String nextLine() throws IOException
		{
			return br.readLine();
		}
		public String next() throws IOException
		{
			while(st==null || !st.hasMoreTokens())
				st=new StringTokenizer(br.readLine());
			return st.nextToken();
		}
		public int nextInt() throws IOException
		{
			return Integer.parseInt(next());
			
		}
		public double nextDouble() throws IOException
		{
			return Double.parseDouble(next());
		}
		public boolean ready() throws IOException
		{
			return br.ready();
		}
		public long nextLong() throws IOException
		{
			return Long.parseLong(next());
		}
	}
}
