#include <bits/stdc++.h>
using namespace std;
const int INF = 1e9;
template <typename T>
void alert(T const &t) {
  cout << t << endl;
  exit(0);
}
struct node_t {};
int n, m;
vector<string> v;
bool solve(int i) {
  set<int> js;
  for (int j = 0; j < m; ++j) {
    if (v[i][j] == '#') {
      js.insert(j);
    }
  }
  for (int i = 0; i < n; ++i) {
    int ans = 0;
    for (int j = 0; j < m; ++j) {
      if (v[i][j] == '#' && js.count(j)) {
        ++ans;
      }
    }
    if (ans && ans != js.size()) {
      return false;
    }
  }
  return true;
}
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  cin >> n >> m;
  v.resize(n);
  for (string &vi : v) cin >> vi;
  for (int i = 0; i < n; ++i) {
    if (!solve(i)) {
      alert("No");
    }
  }
  alert("Yes");
  return 0;
}
