9 5
.....
#....
..#..
.....
.#..#
...#.
.#...
....#
.....
 4 10
..#......#
.....##...
#.........
.#.......#
 50 2
..
..
#.
..
.#
..
..
..
.#
..
..
.#
##
..
..
..
.#
..
..
.#
..
..
.#
..
..
.#
..
.#
..
.#
..
.#
.#
.#
..
..
..
.#
.#
.#
..
..
.#
.#
..
..
..
..
..
..
 2 50
...#.##.###...#.#..##....##..........#.#..#.#####.
...#.##.###...#.#..##....##..........#.#..#.#####.
 1 1
#
 3 3
.##
#.#
##.
 50 8
.....#..
........
........
.....#..
.....#..
........
........
........
........
...#....
...#....
........
...#....
#.#.#...
...#....
...#....
........
...#....
...#....
...#....
........
#.#.#...
.....#..
........
#.#.#...
#.#.#...
#.#.#...
...#....
........
........
........
#.#.#...
........
.....#..
........
........
........
........
........
........
.....#..
........
........
........
.....#..
#.#.#...
...#....
........
........
........
 1 1
.
 25 16
.............#..
.............#..
.......#...#....
............#...
.....#..........
.....#..........
#...............
................
........#.......
................
................
.#..............
#...............
.....#..........
.#..............
............#...
................
................
................
........#.......
..#.............
..........#.....
.......#...#....
.............#..
..........#.....
 25 16
..............#.
................
...#...#........
........#.#.....
..............##
..............#.
.......#........
......#.........
............#...
.........#.....#
..............#.
.......#........
#...........#...
...#.#..........
.#..............
................
......#.....#...
.......#........
........#.....#.
................
......#.........
..#.............
................
...#.#..........
.#..............
 10 15
.......#.......
.....#.........
....#..........
....#..........
.....#.........
.....#.........
#.............#
...#..#........
...............
.............#.
 4 10
###..#..##
...##..#..
.##..#..#.
.........#
 2 5
.####
#..##
 5 2
##
##
..
##
..
 2 2
##
#.
 50 1
.
.
#
.
#
.
#
.
.
#
#
#
.
#
#
#
#
.
.
.
.
.
.
.
.
.
#
#
#
#
.
.
.
.
.
#
.
.
.
#
#
.
.
#
#
.
.
#
#
.
 5 2
#.
##
##
#.
..
 2 3
#.#
###
 2 1
.
#
 2 3
#.#
##.
 10 10
..........
..........
..........
..........
.#.......#
#.........
......#...
..........
..........
#.....#...
 4 4
###.
##.#
#.##
.###

No
 No
 No
 Yes
 Yes
 No
 Yes
 Yes
 Yes
 No
 Yes
 No
 No
 Yes
 No
 Yes
 No
 No
 Yes
 No
 No
 No

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.util.Arrays;
import java.util.StringTokenizer;

public class Main {

  static int T;
  static int n, m;
  static char[][] mat = new char[51][51];
  static long[] bitset = new long[51];

  public static void main(String[] args) {
    FastInput fi = new FastInput(System.in);
//    BufferedWriter writer = new BufferedWriter(new FileWriter("/Users/adityavivek/file.txt"));
    n = fi.nextInt();
    m = fi.nextInt();

    for(int i = 1; i<=n; i++) {
      String s = fi.nextString();
      s = '\0'+s;
      mat[i] = s.toCharArray();
    }

    markBits();
    if (check()) {
      System.out.println("Yes");
    } else {
      System.out.println("No");
    }

  }

  static void markBits() {
    for(int i = 1; i<=n; i++) {
      for(int j = 1; j<=m; j++) {
        if(mat[i][j] == '#') {
          bitset[i] = bitset[i] | (1L<<(j-1));
        }
      }
    }
  }

  static boolean check() {
    for(int i = 1; i<=n; i++) {
      for(int j = 1; j<=n; j++) {
        if(i == j)
          continue;

        if(bitset[i] != bitset[j] && ((bitset[i] & bitset[j]) != 0))
          return false;
        else continue;
      }
    }
    return true;
  }

  private static class FastInput {

    BufferedReader reader;
    StringTokenizer st;

    public FastInput(InputStream inputStream) {
      reader = new BufferedReader(new InputStreamReader(inputStream), 32768);
    }

    String nextString() {
      while(st == null || !st.hasMoreTokens()) {
        try {
          st = new StringTokenizer(reader.readLine());
        } catch (IOException e) {
          throw new RuntimeException(e);
        }
      }
      return st.nextToken();
    }

    int nextInt() {
      return Integer.parseInt(nextString());
    }

    long nextLong() {
      return Long.parseLong(nextString());
    }
  }

}
