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#include <bits/stdc++.h>
using namespace std;
signed main() {
  ios::sync_with_stdio(false);
  cin.tie(0);
  cout.tie(0);
  long long d[60][60];
  long long n, m;
  cin >> n >> m;
  for (long long i = 1; i <= n; i++) {
    for (long long j = 1; j <= m; j++) {
      char c;
      cin >> c;
      if (c == '#')
        d[i][j] = 1;
      else
        d[i][j] = 0;
    }
  }
  vector<long long> str(100, 0), stol(100, 0);
  long long fl = 0, counter = 0;
  for (long long i = 1; i <= n; i++) {
    counter = 0;
    for (long long j = 1; j <= m; j++)
      if (d[i][j] == 1) counter++;
    if (counter > 0) {
      for (long long j = 1; j <= m; j++) {
        if (d[i][j] == 1) {
          if (stol[j] == 0)
            stol[j] = 1;
          else {
            cout << "No";
            return 0;
          }
        }
      }
      for (long long j = i + 1; j <= n; j++) {
        fl = 0;
        for (long long k = 1; k <= m; k++)
          if (d[j][k] != d[i][k]) fl++;
        if (fl == 0) {
          for (long long k = 1; k <= m; k++) d[j][k] = 0;
        }
      }
      for (long long j = 1; j <= m; j++) d[i][j] = 0;
    }
  }
  for (long long i = 1; i <= n; i++)
    for (long long j = 1; j <= m; j++)
      if (d[i][j] > 0) {
        cout << "No";
        return 0;
      }
  cout << "Yes";
  return 0;
}
