#include <bits/stdc++.h>
using namespace std;
const int INF = 20050208;
int row[55];
int col[55];
bool ok = true;
string maze[100];
int main() {
  int n, m;
  cin >> n >> m;
  for (int i = 0; i < n; i++) {
    cin >> maze[i];
  }
  for (int i = 0; i < n; i++) {
    if (row[i] == true) continue;
    for (int j = 0; j < m; j++) {
      if (maze[i][j] == '#') {
        if (col[j] == false) {
          col[j] = true;
          row[i] = true;
        } else {
          ok = false;
          break;
        }
      }
    }
    for (int k = 0; k < n; k++) {
      if (maze[i] == maze[k]) {
        row[k] = true;
      }
    }
  }
  if (ok) {
    cout << "Yes";
  } else {
    cout << "No";
  }
  return 0;
}
