#include
     
      #include
      
       #include
       
        #include
        
         #include
         
          using namespace std;int n;char s[205][205],cmd;int main(){    freopen("puzzle.in","r",stdin);    freopen("puzzle.out","w",stdout);    cin>>n;    for(int i = 1;i <= n;i++){        for(int j = 1;j <= n;j++){            scanf(" %c",&cmd);            s[i][j] = cmd;        }    }    for(int i = 2;i <= n-1;i++){        for(int j = 2;j <= n-1;j++){            if(s[i][j] == '#' && s[i-1][j] == '#' && s[i+1][j] == '#' && s[i][j-1] == '#' && s[i][j+1] == '#'){                s[i][j] = s[i-1][j] = s[i+1][j] = s[i][j-1] = s[i][j+1] = '.';            }        }    }    for(int i = 1;i <= n;i++){        for(int j = 1;j <= n;j++){            if(s[i][j] == '#'){                cout<<"NO";                return 0;            }        }    }    cout<<"YES";    return 0;}