#include <bits/stdc++.h>
constexpr double EPS = 1e-9;
using namespace std;
int sz = 0;
int n, m;
vector<vector<pair<int, int>>> ss;
bool vis[51][51];
string grid[51];
void dfs(int r, int c) {
  vis[r][c] = 1;
  ss[sz].push_back({r, c});
  for (int i = 0; i < n; i++) {
    if (grid[i][c] == '#' && !vis[i][c]) dfs(i, c);
  }
  for (int i = 0; i < m; i++) {
    if (grid[r][i] == '#' && !vis[r][i]) dfs(r, i);
  }
}
int main() {
  cin >> n >> m;
  for (int i = 0; i < n; i++) cin >> grid[i];
  for (int i = 0; i < n; i++) {
    for (int j = 0; j < m; j++) {
      if (grid[i][j] == '#' && !vis[i][j]) {
        ss.push_back(vector<pair<int, int>>());
        dfs(i, j);
        sz++;
      }
    }
  }
  for (auto el : ss) {
    int rr[51] = {0};
    int cc[51] = {0};
    for (auto qq : el) {
      rr[qq.first] = 1;
      cc[qq.second] = 1;
    }
    int a, b;
    a = b = 0;
    for (int i = 0; i < 50; i++) {
      a += rr[i];
      b += cc[i];
    }
    if (a * b != el.size()) {
      cout << "No";
      return 0;
    }
  }
  cout << "Yes";
}
