#include <bits/stdc++.h>
using namespace std;
void solve() {}
int main(void) {
  cin.tie(0), cout.tie(0)->sync_with_stdio(0);
  int n, m;
  cin >> n >> m;
  vector<vector<char>> grid(n, vector<char>(m));
  for (int i = 0; i < n; i++) {
    for (int j = 0; j < m; j++) {
      cin >> grid[i][j];
    }
  }
  for (int i = 0; i < n; i++) {
    for (int j = 0; j < n; j++) {
      bool oneZero = false, oneOne = false;
      for (int k = 0; k < m; k++) {
        if (grid[i][k] == '.') continue;
        if (grid[j][k] != '#') {
          oneZero = true;
        } else if (grid[j][k] == '#') {
          oneOne = true;
        }
      }
      if (oneZero && oneOne) {
        cout << "No\n";
        return 0;
      }
    }
  }
  cout << "Yes\n";
  return 0;
}
