#include <bits/stdc++.h>
using namespace std;
const int N = 110;
vector<pair<int, int> > v;
map<pair<int, int>, bool> mx;
bool a[N][N];
int main() {
  ios_base::sync_with_stdio(false);
  int n;
  char x;
  cin >> n;
  for (int i = 1; i <= n; i++) {
    for (int j = 1; j <= n; j++) {
      cin >> x;
      (x == '.') ? a[i][j] = 0 : a[i][j] = 1;
      if (a[i][j] == 1) {
        mx[make_pair(i, j)] = 1;
        v.push_back(make_pair(i, j));
      }
    }
  }
  bool ch = 0;
  for (int i = 0; i < v.size(); i++) {
    if (a[v[i].first][v[i].second] == 0) continue;
    if (a[v[i].first + 1][v[i].second - 1] == 1 &&
        a[v[i].first + 1][v[i].second] == 1 &&
        a[v[i].first + 1][v[i].second] == 1 &&
        a[v[i].first + 2][v[i].second] == 1) {
      a[v[i].first][v[i].second] = 0;
      a[v[i].first + 1][v[i].second - 1] = 0;
      a[v[i].first + 1][v[i].second] = 0;
      a[v[i].first + 1][v[i].second + 1] = 0;
      a[v[i].first + 2][v[i].second] = 0;
    } else {
      ch = 1;
      break;
    }
  }
  (ch == 1) ? cout << "NO" : cout << "YES";
}
