#include <bits/stdc++.h>
using namespace std;
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(nullptr);
  int n, m;
  cin >> n >> m;
  vector<vector<char> > arr(n, vector<char>(m));
  for (int i = 0; i < n; ++i) {
    for (int j = 0; j < m; ++j) {
      cin >> arr[i][j];
    }
  }
  vector<int> col(m, 0);
  vector<int> row(n, 0);
  bool res = true;
  for (int i = 0; i < n; ++i) {
    if (!row[i]) {
      row[i] = 1;
      bool fl = true;
      for (int j = 0; j < m; ++j) {
        if (arr[i][j] == '#') {
          if (col[j]) {
            fl = false;
            break;
          } else {
            col[j] = 1;
          }
        }
      }
      if (!fl) {
        res = false;
        break;
      }
      for (int j = i + 1; j < n; ++j) {
        bool fl1 = true;
        for (int r = 0; r < m; ++r) {
          if (arr[i][r] != arr[j][r]) {
            fl1 = false;
            break;
          }
        }
        if (fl1) {
          row[j] = 1;
        }
      }
    }
  }
  if (res) {
    cout << "Yes";
  } else {
    cout << "No";
  }
  return 0;
}
