#include <bits/stdc++.h>
using namespace std;
char a[100][100];
vector<string> str[100];
int main() {
  long long int n, i, j, k, x, y, m, row, col;
  string s;
  cin >> row >> col;
  for (i = 0; i < row; i++) {
    cin >> s;
    str[i].push_back(s);
    for (j = 0; j < col; j++) a[i][j] = s[j];
  }
  for (i = 0; i < row; i++) {
    for (j = 0; j < col; j++) {
      if (a[i][j] == '#') {
        for (k = 0; k < row; k++) {
          if (a[k][j] == '#') {
            if (str[i] != str[k]) {
              printf("No\n");
              return 0;
            }
          }
        }
      }
    }
  }
  printf("Yes\n");
}
