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

/**
 * Built using CHelper plug-in
 * Actual solution is at the top
 */
public class Main {
    public static void main(String[] args) {
        InputStream inputStream = System.in;
        OutputStream outputStream = System.out;
        InputReader in = new InputReader(inputStream);
        PrintWriter out = new PrintWriter(outputStream);
        TaskB solver = new TaskB();
        solver.solve(1, in, out);
        out.close();
    }

    static class TaskB {
        public void solve(int testNumber, InputReader in, PrintWriter out) {
            int n = in.nextInt();
            int m = in.nextInt();
            boolean[][] black = new boolean[n][m];
            String[] temp = new String[n];
            for (int i = 0; i < n; i++) {
                String str = in.next();
                temp[i] = str;
                for (int j = 0; j < m; j++) {
                    black[i][j] = str.charAt(j) == '#';
                }
            }
            boolean[] rColored = new boolean[n];
            boolean[] cColored = new boolean[m];
            for (int i = 0; i < n; i++) {
                if (rColored[i]) continue;
                for (int j = 0; j < m; j++) {
                    if (black[i][j]) {
                        if (cColored[j]) {
                            System.out.println("end");
                            out.println("No");
                            return;
                        }
                        for (int k = i + 1; k < n; k++) {
                            if (!black[k][j]) continue;
                            if (!rColored[k] && !temp[i].equals(temp[k])) {
                                out.println("No");
                                return;
                            } else {
                                rColored[k] = true;
                            }
                        }
                        cColored[j] = true;
                    }
                }
            }
            out.println("Yes");
        }

    }

    static 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 int nextInt() {
            return Integer.parseInt(next());
        }

    }
}

