#include <bits/stdc++.h>
using namespace std;
int n, m;
string st[55];
bool h_used[55], v_used[55];
vector<int> hor[55];
int main() {
  cin >> n >> m;
  for (int i = 0; i < n; ++i) {
    cin >> st[i];
    for (int j = 0; j < m; ++j) {
      if (st[i][j] == '#') {
        hor[i].push_back(j);
      }
    }
  }
  for (int i = 0; i < n; ++i) {
    for (int j = 0; j < hor[i].size(); ++j) {
      int k = hor[i][j];
      for (int u = 0; u < n; ++u) {
        if (st[u][k] == '#' && hor[i] != hor[u]) {
          cout << "No";
          return 0;
        }
      }
    }
  }
  cout << "Yes";
}
