#include <bits/stdc++.h>
using namespace std;
const int maxn = 55;
char mas[maxn][maxn];
bool used1[maxn];
bool used2[maxn];
inline int solve() {
  int n, m;
  cin >> n >> m;
  for (int i = 0; i < n; ++i) {
    for (int j = 0; j < m; ++j) {
      cin >> mas[i][j];
    }
  }
  for (int i = 0; i < n; ++i) {
    vector<int> ids;
    for (int j = 0; j < m; ++j) {
      if (mas[i][j] == '#') ids.push_back(j);
    }
    if (ids.empty()) continue;
    if (used1[i]) {
      cout << "No";
      return 0;
    }
    for (int k = i + 1; k < n; ++k) {
      bool isneed = false;
      for (auto l : ids) {
        if (mas[k][l] == '#') isneed = true;
      }
      if (isneed) {
        if (used1[k]) {
          cout << "No";
          return 0;
        }
        used1[k] = true;
        for (auto l : ids) {
          if (mas[k][l] == '.') {
            cout << "No";
            return 0;
          } else {
            mas[k][l] = '.';
          }
        }
      }
    }
  }
  cout << "Yes";
}
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(0);
  solve();
  return 0;
}
