#include <bits/stdc++.h>
using namespace std;
template <typename T>
std::ostream &operator<<(std::ostream &out, vector<T> &v) {
  for (typename vector<T>::size_type i = 0; i < v.size(); ++i)
    out << v[i] << " ";
  out << "\n";
  return out;
}
template <typename T, typename N>
std::ostream &operator<<(std::ostream &out, vector<pair<T, N> > &v) {
  for (size_t i = 0; i < v.size(); ++i)
    out << "(" << v[i].first << ", " << v[i].second << ") ";
  out << "\n";
  return out;
}
template <typename T>
std::ostream &operator<<(std::ostream &out, vector<vector<T> > &v) {
  for (size_t i = 0; i < v.size(); ++i) {
    for (size_t j = 0; j < v[i].size(); ++j) {
      out << v[i][j] << " ";
    }
    out << "\n";
  }
  return out;
}
int main() {
  std::ios::sync_with_stdio(false);
  cin.tie(0);
  cout.tie(0);
  int n, m;
  cin >> n >> m;
  vector<string> grid(n);
  for (int i = 0; i < n; ++i) {
    cin >> grid[i];
  }
  set<int> rows, cols;
  int rows_set = 0;
  while (rows_set < n) {
    string curr_row = "";
    for (int i = 0; i < n; ++i) {
      if (!rows.count(i)) {
        curr_row = grid[i];
        rows.insert(i);
        for (int j = i + 1; j < n; ++j) {
          if (grid[j] == curr_row) {
            rows.insert(j);
            ++rows_set;
          }
        }
        for (int j = 0; j < m; ++j) {
          if (grid[i][j] == '#' && cols.count(j)) {
            cout << "No\n";
            return 0;
          }
          if (grid[i][j] == '#') {
            cols.insert(j);
            cerr << "> "
                 << "j"
                 << ": " << j << "\n";
            ;
          }
        }
        ++rows_set;
      }
    }
  }
  cout << "Yes\n";
  return 0;
}
