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