#include <bits/stdc++.h>
using namespace std;
char arr[110][110];
bool arr1[110][110], f = 1;
int main() {
  int n;
  cin >> n;
  for (int i = 0; i < n; i++) {
    for (int j = 0; j < n; j++) {
      cin >> arr[i][j];
    }
  }
  for (int i = 0; i < n; i++) {
    for (int j = 0; j < n; j++) {
      if (arr[i][j] == '#' && arr1[i][j] == 0) {
        if (arr[i + 1][j + 1] == '#' && arr1[i + 1][j + 1] == 0 &&
            arr[i + 1][j - 1] == '#' && arr1[i][j - 2] == 0 &&
            arr[i + 1][j] == '#' && arr1[i + 1][j] == 0 &&
            arr[i + 2][j] == '#' && arr1[i + 2][j] == 0) {
          arr[i][j] = 1;
          arr[i + 1][j - 1] = 1;
          arr[i + 1][j] = 1;
          arr[i + 1][j + 1] = 1;
          arr[i + 2][j] = 1;
        } else {
          f = false;
          i = n;
          j = n;
          break;
        }
      }
    }
  }
  if (f == true)
    cout << "YES";
  else
    cout << "NO";
  return 0;
}
