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No
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 No


import java.io.*;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.HashSet;
import java.util.Set;

public class Main {
    
    public static void main(String[] args) throws IOException {
        BufferedReader in = new BufferedReader(new InputStreamReader(System.in));
        PrintWriter out = new PrintWriter(System.out);
        String[] x = in.readLine().split(" ");
        int n = Integer.parseInt(x[0]);
        int m = Integer.parseInt(x[1]);
        char tab[][] = new char[n][m];
        for (int i = 0; i < n; i++) {
            String ch = in.readLine();
            tab[i] = ch.toCharArray();
        }
        ArrayList<Integer>[] p = (ArrayList<Integer>[]) new ArrayList[51];
        HashSet<ArrayList<Integer>> s = new HashSet<>();
        for (int i = 0; i < n; i++) {
            for (int j = 0; j < m; j++) {
                if (tab[i][j] == '#') {
                    if (p[i] == null) {
                        p[i] = new ArrayList<>();
                        p[i].add(j);
                    } else {
                        p[i].add(j);
                    }
                }
            }
        }
        
        for (ArrayList<Integer> elt : p) {
            if (elt != null) {
                s.add(elt);
            }
        }
        Set<Integer> set = new HashSet<>();
       // out.print(s.toString());
        for (ArrayList<Integer> arrayList : s) {
            for (Integer integer : arrayList) {
                if (set.contains(integer)) {
                    out.println("No");
                    out.close();
                    return;
                } else {
                    set.add(integer);
                }
            }
        }
        out.print("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;
        }
        
    }
    
}
