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import java.io.*;
import java.lang.reflect.Array;
import java.util.*;
import static java.lang.Math.*;


public class Main
{

    public static void solve(FastScanner in, BufferedWriter out) throws IOException {
        int r = in.nextInt(), c = in.nextInt();
        char[][] grid = new char[r][c];

        for (int i = 0; i < r; i++) {
            String row = in.next();
            for (int j = 0; j < c; j++) {
                grid[i][j] = row.charAt(j);
            }
        }


        //if a cell is black in a row, col and same col is also set in other row then both rows must be same
        // because same row or columns can not be selected again to flip it.

        boolean isValid = true;
        outer: for (int i = 0; i < r; i++) {
            for (int j = 0; j < c ; j++) {
                if(grid[i][j] == '#') {
                    for (int k = i+1; k < r; k++) {
                        if(grid[k][j] == '#') {
                            //match row
                            for (int m = 0; m < c; m++) {
                                if(grid[k][m] != grid[i][m]) {
                                    isValid = false;
                                    break outer;
                                }
                            }
                        }
                    }
                }
            }
        }

        out.append(isValid? "Yes" : "No");
    }

    /**************** ENTER HERE   ********************/
    public static void main(String[] args) throws Exception
    {
        FastScanner fscan = new FastScanner(System.in);
        BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(System.out));
        solve(fscan,bw);
        bw.close();
    }
}


class FastScanner {
    StringTokenizer st;
    BufferedReader br;

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

    public void nextIntArray(int[] a) throws IOException
    {
        for(int i =0;i<a.length;i++)
            a[i] = nextInt();
    }

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

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

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

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