#include <bits/stdc++.h>
using namespace std;
string s[51];
int n, m;
bool check(int i, int j) {
  for (int k = 1; k <= n; ++k)
    if (s[k][j] == '#' && s[k] != s[i]) return false;
  return true;
}
signed main() {
  ios::sync_with_stdio(false);
  cin >> n >> m;
  for (int i = 1; i <= n; ++i) cin >> s[i];
  for (int i = 1; i <= n; ++i)
    for (int j = 0; j <= m - 1; ++j)
      if (s[i][j] == '#')
        if (!check(i, j)) {
          cout << "No";
          return 0;
        }
  cout << "Yes";
  return 0;
}
