#include <bits/stdc++.h>
using namespace std;
int main() {
  int n, m;
  char mp[100][100];
  scanf("%d%d", &n, &m);
  for (int i = 0; i < n; i++) scanf("%s", mp[i]);
  int row[100], col[100];
  memset(row, 0, sizeof(row));
  memset(col, 0, sizeof(col));
  int flag = 0;
  for (int i = 0; i < n; i++) {
    int j;
    if (row[i] == 1) continue;
    for (j = 0; j < m; j++) {
      if (mp[i][j] == '#') break;
    }
    if (j == m) continue;
    row[i] = 1;
    for (j = i + 1; j < n; j++) {
      if (strcmp(mp[i], mp[j]) == 0) {
        row[j] = 1;
      }
    }
    for (j = 0; j < m; j++) {
      if (mp[i][j] == '#') {
        if (col[j] == 1) {
          flag = 1;
          break;
        } else
          col[j] = 1;
      }
    }
    if (flag) break;
  }
  if (flag)
    printf("No\n");
  else
    printf("Yes\n");
  return 0;
}
