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import java.io.*;
import java.util.*;
import java.io.IOException;
import java.io.InputStream;


public class Main {
    public static void main(String[] args) {

        File file = new File("in.txt");
        File fileOut = new File("out.txt");
        InputStream inputStream = null;
        OutputStream outputStream = null;
//         try {inputStream= new FileInputStream(file);} catch (FileNotFoundException ex){return;};
//        try {outputStream= new FileOutputStream(fileOut);} catch (FileNotFoundException ex){return;};
        inputStream = System.in;
        outputStream = System.out;
        InputReader in = new InputReader(inputStream);
        PrintWriter out = new PrintWriter(outputStream);
        Task solver = new Task();
        solver.solve(1, in, out);
        out.close();
    }


}

class Tank implements java.lang.Comparable<Tank>{
	int i;
	int remainder;
	
	public Tank(int i,int remainder){
		this.i = i;
		this.remainder = remainder;
	}
	
	@Override
	public int compareTo(Tank o){
		return this.remainder - remainder;
	}
}

class Task {
	
	public boolean isWildcard(char a){
		return (a=='?'?true:false);
	}

    public void solve(int testNumber, InputReader in, PrintWriter out) {
		int n = in.nextInt();
		int m = in.nextInt();
		
		boolean grid[][] = new boolean[n][m];
		for(int i=0;i<n;i++){
			String s = in.nextLine();
			for(int j=0;j<m;j++){
				grid[i][j] = (s.charAt(j) == '.'? false : true);
			}
		}
		
		int groups[] = new int[n];
		int groups1[] = new int[m];
		int cnt = 1;
		boolean result = true;
		
		
		for(int j=0;j<m;j++){
			int curr_group = 0;
			for(int i=0;i<n;i++){
				if(grid[i][j]){
					if(curr_group == 0){
						if(groups[i] == 0){
							curr_group = cnt++;
							groups[i] = curr_group;
						}else{
							curr_group = groups[i];
						}
						groups1[j] = curr_group;
					}else{
						if(groups[i] == 0){
							groups[i] = curr_group;
						}
						if(groups[i] != curr_group){
							result = false;
							break;
						}
					}
				}
			}
		}
		
		for(int j=0;j<m;j++){
			for(int i=0;i<n;i++){
				if(!grid[i][j] && groups[i] == groups1[j]){
					result = false;
					break;
				}
			}
		}
		
		if(result)
			out.println("Yes");
		else
			out.println("No");
	}
}

class InputReader {
    public BufferedReader reader;
    public StringTokenizer tokenizer;

    public InputReader(InputStream stream) {
        reader = new BufferedReader(new InputStreamReader(stream), 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 String nextLine(){
        try {
            return reader.readLine();
        } catch (IOException e){
            throw new RuntimeException(e);
        }
    }

    public int nextInt() {
        return Integer.parseInt(next());
    }
    public long nextLong() { return Long.parseLong(next()); }

}