#include #include #include #include #include #include #include #include #include #include #include #include #include using namespace std; typedef long long ll; #define i_7 1000000007 #define i_5 1000000005 ll mod(ll a){ ll c=a%i_7; if(c>=0)return c; else return c+i_7; } typedef pair i_i; typedef pair l_l; #define inf 100000000/*10^8*/ #define rep(i,l,r) for(int i=l;i<=r;i++) const double EPS=1E-8; //////////////////////////////////////// int h,w; char p[50][50+1]; bool flag=false; void solve(int x,int y){ char m[h][51]; rep(i,0,h-1)rep(j,0,w-1)m[i][j]=p[i][j]; rep(i,0,h-1)rep(j,0,w-1){ if(m[i][j]=='#'){ m[i][j]='.'; if(i+x>=h||j+y>=w)return; if(m[i+x][j+y]=='.')return; m[i+x][j+y]='.'; } } cout<<"YES"; flag=true; } int main(){ cin>>h>>w; rep(i,0,h-1)cin>>p[i]; rep(i,0,h-1){ rep(j,0,w-1){ solve(i,j); } } if(!flag)cout<<"NO"; return 0; }