#include <bits/stdc++.h>
using namespace std;
int const N = 1000020;
string a[51];
char ans[51][51];
int n, m;
set<int> rs, cs;
int h[51][51];
int main() {
  cin >> n >> m;
  for (int i = 0; i < n; i++) {
    cin >> a[i];
  }
  for (int i = 0; i < n; i++) {
    for (int i2 = 0; i2 < n; i2++) {
      for (int j = 0; j < m; j++) {
        if (a[i][j] == '#' && a[i2][j] == '#') {
          for (int j2 = 0; j2 < m; j2++) {
            if (a[i][j2] != a[i2][j2]) {
              cout << "No";
              return 0;
            }
          }
        }
      }
    }
  }
  cout << "Yes";
  return 0;
}
