#include <bits/stdc++.h>
using namespace std;
const double PI = acos(-1.0);
int main() {
  ios::sync_with_stdio(0);
  cin.tie(0);
  int n, m;
  cin >> n >> m;
  bool **map = new bool *[n];
  for (int i = 0; i < n; ++i) {
    map[i] = new bool[m];
    for (int j = 0; j < m; ++j) {
      char c;
      cin >> c;
      map[i][j] = c == '#';
    }
  }
  bool *r = new bool[n];
  fill(r, r + n, false);
  bool can = true;
  for (int i = 0; i < n; ++i) {
    if (r[i]) {
      continue;
    }
    r[i] = true;
    vector<int> list;
    for (int j = 0; j < m; ++j) {
      if (map[i][j]) {
        list.push_back(j);
      }
    }
    if ((list).size() == 0) {
      continue;
    }
    for (int j = i + 1; j < n; ++j) {
      if (r[j]) {
        continue;
      }
      bool f = false;
      for (int k = 0; k < (list).size(); ++k) {
        if (map[j][list[k]]) {
          f = true;
          break;
        }
      }
      if (!f) {
        continue;
      }
      r[j] = true;
      bool ff = false;
      for (int k = 0; k < m; ++k) {
        if (map[j][k] != map[i][k]) {
          ff = true;
          break;
        }
      }
      if (ff) {
        can = false;
        break;
      }
    }
    if (!can) {
      break;
    }
  }
  cout << (can ? "Yes" : "No") << endl;
  return 0;
}
