#include <bits/stdc++.h>
using namespace std;
void dfs(long long i, long long j, vector<vector<long long> >& d,
         vector<long long>& fg, vector<long long>& fv, long long& er) {
  fg[i] = fv[j] = 1;
  d[i][j] = 0;
  long long n = d.size();
  long long m = d[0].size();
  for (long long(k) = 0; (k) < (m); ++(k)) {
    if (d[i][k]) {
      dfs(i, k, d, fg, fv, er);
    }
  }
  for (long long(k) = 0; (k) < (n); ++(k)) {
    if (d[k][j]) {
      dfs(k, j, d, fg, fv, er);
    }
  }
}
void solve() {
  long long n, m;
  cin >> n >> m;
  vector<vector<long long> > d(n, vector<long long>(m, 0));
  long long cnt = 0;
  for (long long(i) = 0; (i) < (n); ++(i)) {
    for (long long(j) = 0; (j) < (m); ++(j)) {
      char c;
      cin >> c;
      if (c == '#') {
        d[i][j] = 1;
        ++cnt;
      }
    }
  }
  long long er = 0;
  for (long long(i) = 0; (i) < (n); ++(i)) {
    for (long long(j) = 0; (j) < (m); ++(j)) {
      if (d[i][j]) {
        vector<long long> fg(n, 0);
        vector<long long> fv(m, 0);
        dfs(i, j, d, fg, fv, er);
        for (long long(g) = 0; (g) < (n); ++(g)) {
          for (long long(v) = 0; (v) < (m); ++(v)) {
            if (fg[g] && fv[v]) {
              if (d[g][v]) {
                er = 1;
              } else {
                --cnt;
              }
            }
          }
        }
      }
    }
  }
  if (cnt) {
    er = 1;
  }
  cout << (er ? "No" : "Yes") << endl;
}
int main() {
  ios::sync_with_stdio(false);
  solve();
  return 0;
}
