#include <bits/stdc++.h>
using namespace std;
int main() {
  int n;
  cin >> n;
  vector<string> arr(n);
  int i, j;
  for (i = 0; i < n; i++) cin >> arr[i];
  int visited[101][101] = {0};
  for (i = 0; i < n; i++) {
    for (j = 0; j < n; j++) {
      if (arr[i][j] == '.') visited[i][j] = 1;
    }
  }
  for (i = 0; i < n - 2; i++) {
    for (j = 1; j < n - 1; j++) {
      if (arr[i][j] == '#' && arr[i + 1][j - 1] == '#' &&
          arr[i + 1][j] == '#' && arr[i + 1][j + 1] == '#' &&
          arr[i + 2][j] == '#') {
        arr[i][j] = '.';
        arr[i + 1][j - 1] = '.';
        arr[i + 1][j] = '.';
        arr[i + 1][j + 1] = '.';
        arr[i + 2][j] = '.';
        visited[i][j] = 1;
        visited[i + 1][j - 1] = 1;
        visited[i + 1][j] = 1;
        visited[i + 1][j + 1] = 1;
        visited[i + 2][j] = 1;
      }
    }
  }
  int flag = 0;
  for (i = 0; i < n; i++) {
    for (j = 0; j < n; j++) {
      if (visited[i][j] == 0) {
        flag = 1;
        break;
      }
    }
  }
  if (flag == 0)
    cout << "YES" << endl;
  else
    cout << "NO" << endl;
  return 0;
}
