#include <bits/stdc++.h>
using namespace std;
const long long int MOD = 1e9 + 7;
signed main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  long long int n, m;
  cin >> n >> m;
  char a[n][m];
  for (long long int i = 0; i < n; i++) {
    for (long long int j = 0; j < m; j++) {
      cin >> a[i][j];
    }
  }
  long long int poss = true;
  for (long long int i = 0; i < n; i++) {
    vector<long long int> vec;
    for (long long int j = 0; j < m; j++) {
      if (a[i][j] == '#') {
        vec.push_back(j);
      }
    }
    if (!vec.empty()) {
      char temp[n];
      for (long long int k = 0; k < n; k++) {
        temp[k] = a[k][vec[0]];
      }
      for (long long int j : vec) {
        for (long long int k = 0; k < n; k++) {
          if (temp[k] != a[k][j]) {
            poss = false;
            cout << "No" << endl;
            return 0;
          }
        }
      }
    }
  }
  cout << "Yes" << endl;
  return 0;
}
