#include <bits/stdc++.h>
using namespace std;
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  int n, m;
  cin >> n >> m;
  vector<string> grid(n);
  for (int i = 0; i < n; i++) cin >> grid[i];
  set<int> cols;
  bool flag = true;
  for (int i = 0; i < n; i++) {
    if (!flag) break;
    for (int j = 0; j < m; j++) {
      if (grid[i][j] == '#') {
        if (cols.count(j) > 0) {
          for (int k = i - 1; k >= 0; k--) {
            if (grid[k][j] == '#') {
              if (grid[k] != grid[i]) flag = false;
            }
          }
        } else
          cols.insert(j);
      }
    }
  }
  if (flag)
    cout << "Yes\n";
  else
    cout << "No\n";
}
