#include <bits/stdc++.h>
using namespace std;
bool check[51];
int main() {
  ios::sync_with_stdio(false);
  cin.tie(0);
  cout.tie(0);
  int n, m;
  cin >> n >> m;
  string s[51];
  for (int i = 0; i < n; i++) cin >> s[i];
  bool finalans = true;
  for (int i = 0; i < n; i++) {
    if (check[i]) continue;
    check[i] = true;
    vector<int> colc;
    for (int j = 0; j < m; j++)
      if (s[i][j] == '#') colc.push_back(j);
    for (int j = i + 1; j < n; j++) {
      if (check[j]) continue;
      bool ans = false;
      for (int nxt : colc)
        if (s[j][nxt] == '#') ans = true;
      if (ans && !colc.empty()) {
        int idx = 0;
        int csize = colc.size();
        for (int k = 0; k < m; k++) {
          if (idx < csize && colc[idx] == k) {
            if (s[j][colc[idx]] != '#') finalans = false;
            idx++;
            continue;
          }
          if (s[j][k] == '#') finalans = false;
        }
      }
      if (ans && finalans) check[j] = true;
    }
  }
  if (finalans)
    cout << "Yes" << '\n';
  else
    cout << "No" << '\n';
  return 0;
}
