#include <bits/stdc++.h>
using namespace std;
int n, m;
char grid[55][55];
bool done[55];
int main() {
  scanf("%d%d", &n, &m);
  for (int i = 0; i < n; ++i) {
    for (int j = 0; j < m; ++j) {
      scanf(" %c", &grid[i][j]);
    }
  }
  for (int i = 0; i < n; ++i) {
    if (done[i]) continue;
    done[i] = true;
    for (int j = i + 1; j < n; ++j) {
      for (int k = 0; k < m; ++k) {
        if (grid[i][k] == '#' && grid[j][k] == '#') {
          string s1 = grid[i], s2 = grid[j];
          if (s1 != s2) {
            printf("No");
            return 0;
          }
          done[j] = true;
        }
      }
    }
  }
  printf("Yes");
  return 0;
}
