#include <bits/stdc++.h>
using namespace std;

int main() {
  int H,W;
  cin>>H>>W;
  char a;
  char vec[H][W];
  for(int k=0; k<H; k++ ){
  for(int j=0; j<W; j++){
  cin>>a;
  vec[k][j]=a;}}
  for(int k=0; k<H-1; k++ ){
  for(int j=0; j<W-1; j++){
  if(vec[k][j]="#"&&vec[k][j+1]="."&&vec[k+1][j]="."){ 
  cout<<"No"<<endl;
  break;}
  else if(k==H-2&&j==W-2)
  cout<<"No"<<endl;
  else continue;}}}
  
