#include <bits/stdc++.h>
using namespace std;
const int INF = int(1e9);
const int N = 60;
int cntRow[N];
int main() {
  int n, m;
  scanf("%d%d", &n, &m);
  char grid[n][m];
  for (int i = 0; i < n; ++i) {
    for (int j = 0; j < m; ++j) {
      cin >> grid[i][j];
      cntRow[i] += (grid[i][j] == '#') << j;
    }
  }
  for (int i = 0; i < n; ++i) {
    for (int j = 0; j < m; ++j) {
      if (grid[i][j] == '#') {
        for (int k = 0; k < n; ++k) {
          if (grid[k][j] == '#' && cntRow[i] != cntRow[k]) {
            printf("No\n");
            return 0;
          }
        }
      }
    }
  }
  printf("Yes\n");
  return 0;
}
