#include <bits/stdc++.h>
int n, m;
bool **Grid;
bool *usedArr;
std::vector<int> getPainted(int i) {
  std::vector<int> result;
  result.reserve(m);
  for (int j = 0; j < m; j++)
    if (Grid[i][j]) result.push_back(j);
  return result;
}
bool check() {
  for (int i = 0; i < n; i++) {
    std::vector<int> painted = getPainted(i);
    if (usedArr[i] && painted.size() != 0) return false;
    if (painted.size() == 0) continue;
    usedArr[i] = true;
    for (int i2 = i + 1; i2 < n; i2++) {
      bool first = Grid[i2][painted[0]];
      Grid[i2][painted[0]] = false;
      if (first) {
        if (usedArr[i2]) return false;
        usedArr[i2] = true;
      }
      for (int j = 1; j < painted.size(); j++) {
        if (Grid[i2][painted[j]] != first) return false;
        Grid[i2][painted[j]] = false;
      }
    }
  }
  return true;
}
int main() {
  scanf("%d%d", &n, &m);
  Grid = new bool *[n];
  usedArr = new bool[n];
  memset(usedArr, 0, n);
  for (int i = 0; i < n; i++) {
    Grid[i] = new bool[m];
    for (int j = 0; j < m; j++) {
      char c;
      scanf(" %c", &c);
      Grid[i][j] = (c == '#');
    }
  }
  printf(check() ? "Yes" : "No");
  return 0;
}
