#include <bits/stdc++.h>
using namespace std;
int main() {
  ios::sync_with_stdio(false);
  cin.tie(nullptr);
  cout.tie(nullptr);
  int n, m;
  cin >> n >> m;
  set<string> second;
  vector<string> b;
  for (int i = 0; i < n; i++) {
    string a;
    cin >> a;
    second.insert(a);
  }
  for (auto p : second) b.push_back(p);
  n = b.size();
  for (int i = 0; i < n; i++) {
    for (int j = 0; j < m; j++) {
      if (b[i][j] == '#') {
        for (int tmp = i + 1; tmp < n; tmp++) {
          if (b[tmp][j] == '#') {
            cout << "No";
            return 0;
          }
        }
      }
    }
  }
  cout << "Yes";
}
