#include <bits/stdc++.h>
using namespace std;
const long long mod = 1000000007;
const int maxn = 1e5 + 100;
const int INF = 0x3f3f3f3f;
const double PI = acos(-1.0);
char s[101][101];
int dp[maxn];
int find(int x) {
  if (dp[x] != x) return dp[x] = find(dp[x]);
  return x;
}
int main() {
  int n, m;
  scanf("%d%d", &n, &m);
  for (int i = 1; i <= n; i++) scanf("%s", s[i] + 1);
  for (int i = 1; i <= n + m; i++) dp[i] = i;
  for (int i = 1; i <= n; i++)
    for (int j = 1; j <= m; j++) {
      if (s[i][j] == '#') {
        int u = find(i), v = find(j + n);
        dp[v] = u;
      }
    }
  for (int i = 1; i <= n; i++)
    for (int j = 1; j <= m; j++) {
      if (s[i][j] != '#') {
        int u = find(i), v = find(j + n);
        if (u == v) {
          printf("No\n");
          return 0;
        }
      }
    }
  printf("Yes\n");
  return 0;
}
