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No
 No
 No
 Yes
 Yes
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 No
 No


import java.io.*;
import java.util.*;
import static java.lang.Math.*;
import static java.util.Arrays.*;

public class CF {

    public static void main(String[] args) throws IOException {
        FastScanner in = new FastScanner(System.in);
        PrintWriter out = new PrintWriter(System.out);
        int n = in.nextInt();
        int m = in.nextInt();
        String[] tab = new String[n];
        for (int i = 0; i < n; i++) {
            tab[i] = in.next();
        }
        ArrayList<Integer> rows = new ArrayList<>();
        for (int i = 0; i < n; i++) {
            rows.add(i);
        }
        ArrayList<Integer> cols = new ArrayList<>();
        for (int i = 0; i < m; i++) {
            cols.add(i);
        }
        for (int i = 0; i < n; i++) {
            if (rows.contains(i)) {
                for (int j = 0; j < n; j++) {
                    if (tab[i].equals(tab[j])) {
                        if (rows.contains(j)) {
                            rows.remove((Integer) j);
                        } else {
                            out.println("No");
                            out.close();
                            return;
                        }
                    }
                }
                for (int j = 0; j < tab[i].length(); j++) {
                    if (tab[i].charAt(j) == '#') {
                        if (cols.contains(j)) {
                            cols.remove((Integer) j);
                        } else {
                            out.println("No");
                            out.close();
                            return;
                        }
                    }
                }
            }
        }
        out.println("Yes");
        out.close();
    }

    static class FastScanner {

        private BufferedReader in;
        private String[] line;
        private int index;
        private int size;

        public FastScanner(InputStream in) throws IOException {
            this.in = new BufferedReader(new InputStreamReader(in));
            init();
        }

        public FastScanner(String file) throws FileNotFoundException {
            this.in = new BufferedReader(new FileReader(file));
        }

        private void init() throws IOException {
            line = in.readLine().split(" ");
            index = 0;
            size = line.length;
        }

        public int nextInt() throws IOException {
            if (index == size) {
                init();
            }
            return Integer.parseInt(line[index++]);
        }

        public long nextLong() throws IOException {
            if (index == size) {
                init();
            }
            return Long.parseLong(line[index++]);
        }

        public float nextFloat() throws IOException {
            if (index == size) {
                init();
            }
            return Float.parseFloat(line[index++]);
        }

        public double nextDouble() throws IOException {
            if (index == size) {
                init();
            }
            return Double.parseDouble(line[index++]);
        }

        public String next() throws IOException {
            if (index == size) {
                init();
            }
            return line[index++];
        }

        public String nextLine() throws IOException {
            if (index == size) {
                init();
            }
            StringBuilder sb = new StringBuilder();
            for (int i = index; i < size; i++) {
                sb.append(line[i]).append(" ");
            }
            return sb.toString();
        }

        private int[] nextIntArray(int n) throws IOException {
            int[] tab = new int[n];
            for (int i = 0; i < tab.length; i++) {
                tab[i] = nextInt();
            }
            return tab;
        }

    }

}
