#include <bits/stdc++.h>
#pragma comment(linker, "/STACK:102400000,102400000")
#pragma GCC optimize("Ofast")
#pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,tune=native")
using namespace std;
const int maxn = 2e5 + 5;
string a[500];
set<int> col[500], row[500];
int ficol[500], firow[500];
int main() {
  ios::sync_with_stdio(false);
  cin.tie(0);
  cout.tie(0);
  int i, j, k, m, n;
  cin >> n >> m;
  for (int i = 0; i < n; ++i) cin >> a[i];
  for (int i = 0; i < n; ++i) {
    for (int j = 0; j < m; ++j) {
      if (a[i][j] == '#') {
        col[j].insert(i);
        row[i].insert(j);
      }
    }
  }
  for (int i = 0; i < m; ++i) {
    if (col[i].empty()) continue;
    int p = *col[i].begin();
    for (auto it : col[i]) {
      if (row[it] != row[p]) {
        cout << "No" << endl;
        return 0;
      }
    }
  }
  cout << "Yes" << endl;
  return 0;
}
