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import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.ArrayList;
import java.util.List;
import java.util.Scanner;
import java.util.Set;


public class Main {


    public static void main(String[] args) throws IOException {
        //BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));
        Scanner in = new Scanner(System.in);
        int n,m;
        n = in.nextInt();
        m = in.nextInt();
        ArrayList< ArrayList<Integer>> st = new ArrayList<>();
        ArrayList< ArrayList<Integer>> form = new ArrayList<>();
        for(int i=0;i<m;i++){
            form.add(new ArrayList<>());
        }
        in.nextLine();
        for(int i=0;i<n;i++){
            String t = in.nextLine();
            //System.out.println(t);
            st.add(new ArrayList<>());
            for(int j=0;j<m;j++){
                if(t.charAt(j)=='#') {
                    st.get(i).add(j);
                    form.get(j).add(i);
                }
            }
        }
        for(int i=0;i<m;i++){
            for(int j=1;j<form.get(i).size();j++)
            {
                //System.out.println(st.get(j));
                //System.out.println(st.get(j-1));
                if(!st.get(form.get(i).get(j)).equals(st.get(form.get(i).get(j-1)))){
                    //System.out.println(i);
                   // System.out.println(st.get(j));
                    //System.out.println(st.get(j-1));
                    System.out.println("No");
                    System.exit(0);
                }
            }
        }
        System.out.println("Yes");
    }
}