#include <bits/stdc++.h>
using namespace std;
int main() {
  ios::sync_with_stdio(0);
  cin.tie(0);
  ;
  int n, m;
  cin >> n >> m;
  vector<string> v;
  for (int i = 0; i < n; i++) {
    string s;
    cin >> s;
    v.push_back(s);
  }
  for (int i = 0; i < n; i++) {
    for (int j = 0; j < m; j++) {
      if (v[i][j] == '#') {
        for (int k = 0; k < n; k++) {
          if (k == i) continue;
          if (v[k][j] == v[i][j] && v[i] != v[k]) {
            cout << "No"
                 << "\n";
            return 0;
          }
        }
      }
    }
  }
  cout << "Yes"
       << "\n";
}
