#include <bits/stdc++.h>
using namespace std;
long long gcd(long long a, long long b) { return b == 0 ? a : gcd(b, a % b); }
const int MAXH = 50;
const int MAXW = 50;
int h, w;
char g[MAXH][MAXW + 1];
int par[MAXH + MAXW], sz[MAXH + MAXW], nrows[MAXH + MAXW], ncols[MAXH + MAXW],
    ncells[MAXH + MAXW];
int find(int x) {
  if (par[x] == x) return x;
  return par[x] = find(par[x]);
}
void unite(int a, int b) {
  a = find(a), b = find(b);
  if (a == b) {
    ++ncells[a];
    return;
  }
  if (sz[b] > sz[a]) swap(a, b);
  par[b] = a, sz[a] += sz[b], nrows[a] += nrows[b], ncols[a] += ncols[b],
  ncells[a] += ncells[b], ++ncells[a];
}
bool solve() {
  for (int i = (0); i < (h + w); ++i)
    par[i] = i, sz[i] = i, nrows[i] = i < h ? 1 : 0, ncols[i] = i >= h ? 1 : 0,
    ncells[i] = 0;
  for (int x = (0); x < (h); ++x)
    for (int y = (0); y < (w); ++y)
      if (g[x][y] == '#') unite(x, h + y);
  for (int i = (0); i < (h + w); ++i)
    if (find(i) == i)
      if (nrows[i] * ncols[i] != ncells[i]) return false;
  return true;
}
void run() {
  scanf("%d%d", &h, &w);
  for (int x = (0); x < (h); ++x) scanf("%s", g[x]);
  printf("%s\n", solve() ? "Yes" : "No");
}
int main() {
  run();
  return 0;
}
