#include <bits/stdc++.h>   using namespace std;   int main() {     ios_base::sync_with_stdio(false);     int n;     cin >> n;     vector<string> v(n);     for (int i = 0; i < n; i++) cin >> v[i];     for (int i = 1; i < n - 1; i++) {       for (int j = 1; j < n - 1; j++) {         if (v[i][j] ==  #  and v[i + 1][j] ==  #  and v[i][j + 1] ==  #  and             v[i][j - 1] ==  #  and v[i - 1][j] ==  # ) {           v[i][j] =  a ;           v[i + 1][j] =  a ;           v[i][j + 1] =  a ;           v[i][j - 1] =  a ;           v[i - 1][j] =  a ;         }       }     }     int c = 0;     for (int i = 0; i < n; i++)       for (int j = 0; j < n; j++)         if (v[i][j] ==  # ) {           c = 1;           break;         }     if (c)       cout <<  NO  << endl;     else       cout <<  YES  << endl;     return 0;   }   