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import java.io.BufferedReader;
// import java.io.FileInputStream;
// import java.io.FileOutputStream;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.IOException;
import java.io.PrintWriter;
import java.util.*;

import static java.lang.Math.*;
import static java.util.Arrays.sort;
import static java.util.Collections.reverseOrder;
import static java.util.Collections.sort;

public class Main {
    FastScanner in;
    PrintWriter out;

    private void solve() throws IOException {
        int n = in.nextInt(), m = in.nextInt();
        boolean[][] a = new boolean[n][m];
        boolean[][] b = new boolean[m][n];
        char[] s;
        for (int i = 0; i < n; i++) {
            s = in.nextLine().toCharArray();
            for (int j = 0; j < m; j++) {
                a[i][j] = b[j][i] = s[j] == '#';
            }
        }

        out.print(solve(a) && solve(b) ? "Yes" : "No");
    }

    private boolean solve(boolean[][] a) {
        int n = a.length;
        for (int i = 0; i < n; i++) {
            for (int j = i + 1; j < n; j++) {
                if (!cmp(a[i], a[j])) {
                    return false;
                }
            }
        }
        return true;
    }

    private boolean cmp(boolean[] a, boolean[] b) {
        int n = a.length;

        boolean cmp = false;
        for (int i = 0; i < n; i++) {
            if (a[i] && a[i] == b[i]) {
                cmp = true;
                break;
            }
        }

        return !cmp || Arrays.equals(a, b);
    }

    class FastScanner {
        StringTokenizer st;
        BufferedReader br;

        FastScanner(InputStream s) {
            br = new BufferedReader(new InputStreamReader(s));
        }

        String next() throws IOException {
            while (st == null || !st.hasMoreTokens())
                st = new StringTokenizer(br.readLine());
            return st.nextToken();
        }

        boolean hasNext() throws IOException {
            return br.ready() || (st != null && st.hasMoreTokens());
        }

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

        long nextLong() throws IOException {
            return Long.parseLong(next());
        }

        double nextDouble() throws IOException {
            return Double.parseDouble(next().replace(',', '.'));
        }

        String nextLine() throws IOException {
            return br.readLine();
        }

        boolean hasNextLine() throws IOException {
            return br.ready();
        }
    }

    private void run() throws IOException {
        in = new FastScanner(System.in); // new FastScanner(new FileInputStream(".in"));
        out = new PrintWriter(System.out); // new PrintWriter(new FileOutputStream(".out"));

        solve();

        out.flush();
        out.close();
    }

    public static void main(String[] args) throws IOException {
        new Main().run();
    }
}
