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// package cf957;

import java.io.ByteArrayInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.math.BigInteger;
import java.util.Arrays;
import java.util.InputMismatchException;
import java.util.Set;
import java.util.TreeSet;

public class CFB {
    private static final String INPUT = "5 9\n" +
            "........#\n" +
            "#........\n" +
            "..##.#...\n" +
            ".......#.\n" +
            "....#.#.#";

    FastScanner sc;

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

    public void run() {
        sc = new FastScanner(oj ? System.in : new ByteArrayInputStream(INPUT.getBytes()));

        long s = System.currentTimeMillis();
        solve();
        System.out.flush();
        tr(System.currentTimeMillis() - s + "ms");
    }

    public void solve() {
        int n = sc.nextInt();
        int m = sc.nextInt();

        String[] lines = new String[n];
        for (int i = 0; i < n; i++) {
            lines[i] = sc.nextLine();
        }

        boolean[][] table = new boolean[n][m];
        for (int i = 0; i < n; i++) {
            for (int j = 0; j < m; j++) {
                if (lines[i].charAt(j) == '#') {
                    table[i][j] = true; //filled
                }
            }
        }

        for (int i = 0; i < n; i++) {
            if (lines[i].contains("#")) {
                for (int j = i+1; j < n; j++) {
                    if (lines[j].contains("#")) {
                        if (lines[i].equals(lines[j])) {
                            //OK
                        } else {
//                            boolean cross = false;
                            for (int k = 0; k < m; k++) {
                                if (table[i][k] && table[j][k]) { //both painted;
                                    System.out.println("No");
                                    return;
                                }
                            }
                        }
                    }
                }
            }
        }

        System.out.println("Yes");
    }

    //********************************************************************************************
    //********************************************************************************************
    //********************************************************************************************

    private static int ceil(double d) {
        int ret = (int) d;
        return ret == d ? ret : ret + 1;
    }

    private static int round(double d) {
        return (int) (d + 0.5);
    }

    private static int gcd(int a, int b) {
        BigInteger b1 = BigInteger.valueOf(a);
        BigInteger b2 = BigInteger.valueOf(b);
        BigInteger gcd = b1.gcd(b2);
        return gcd.intValue();
    }

    private static long gcd(long a, long b) {
        BigInteger b1 = BigInteger.valueOf(a);
        BigInteger b2 = BigInteger.valueOf(b);
        BigInteger gcd = b1.gcd(b2);
        return gcd.longValue();
    }

    private int[] readIntArray(int n) {
        int[] res = new int[n];
        for (int i = 0; i < n; i++) {
            res[i] = sc.nextInt();
        }
        return res;
    }

    private long[] readLongArray(int n) {
        long[] res = new long[n];
        for (int i = 0; i < n; i++) {
            res[i] = sc.nextLong();
        }
        return res;
    }

    @SuppressWarnings("unused")
    static class FastScanner {
        private InputStream stream;
        private byte[] buf = new byte[1024];
        private int curChar;
        private int numChars;

        FastScanner(InputStream stream) {
            this.stream = stream;
        }

        int read() {
            if (numChars == -1)
                throw new InputMismatchException();
            if (curChar >= numChars) {
                curChar = 0;
                try {
                    numChars = stream.read(buf);
                } catch (IOException e) {
                    throw new InputMismatchException();
                }
                if (numChars <= 0) return -1;
            }
            return buf[curChar++];
        }

        boolean isSpaceChar(int c) {
            return c == ' ' || c == '\n' || c == '\r' || c == '\t' || c == -1;
        }

        boolean isEndline(int c) {
            return c == '\n' || c == '\r' || c == -1;
        }

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

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

        public double nextDouble() {
            return Double.parseDouble(next());
        }

        public String next() {
            int c = read();
            while (isSpaceChar(c)) c = read();
            StringBuilder res = new StringBuilder();
            do {
                res.appendCodePoint(c);
                c = read();
            } while (!isSpaceChar(c));
            return res.toString();
        }

        public String nextLine() {
            int c = read();
            while (isEndline(c))
                c = read();
            StringBuilder res = new StringBuilder();
            do {
                res.appendCodePoint(c);
                c = read();
            } while (!isEndline(c));
            return res.toString();
        }

    }

    private boolean oj = System.getProperty("ONLINE_JUDGE") != null;

    private void tr(Object... o) {
        if (!oj) System.out.println(Arrays.deepToString(o));
    }
}