#include <bits/stdc++.h>
using namespace std;
int r, c;
char ch[100][100];
vector<int> boo[100];
bool cek(int i, int j) {
  if (boo[i].size() != boo[j].size())
    return false;
  else {
    for (int k = 0; k < boo[i].size(); k++) {
      if (boo[i][k] != boo[j][k]) return false;
    }
  }
  return true;
}
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  cin >> r >> c;
  for (int i = 1; i <= r; i++) {
    for (int j = 1; j <= c; j++) {
      cin >> ch[i][j];
      if (ch[i][j] == '#') boo[i].push_back(j);
    }
  }
  for (int i = 1; i <= r; i++) {
    if (!boo[i].empty()) {
      for (int j = i + 1; j <= r; j++) {
        if (!boo[j].empty()) {
          if (cek(i, j)) {
            boo[j].clear();
          } else {
            for (int k = 0; k < boo[i].size(); k++)
              for (int l = 0; l < boo[j].size(); l++)
                if (boo[i][k] == boo[j][l]) {
                  cout << "No\n";
                  return 0;
                }
          }
        }
      }
      boo[i].clear();
    }
  }
  for (int i = 1; i <= r; i++) {
    if (!boo[i].empty()) {
      cout << "No\n";
      return 0;
    }
  }
  cout << "Yes\n";
}
