#include <bits/stdc++.h>
using namespace std;
set<long long> gera_primos(long long n) {
  set<long long> primos;
  vector<bool> crivo(n + 1);
  primos.insert(2);
  for (long long i = 3; i <= n; i += 2) {
    if (crivo[i]) continue;
    primos.insert(i);
    for (long long j = i; j <= n; j += i) {
      crivo[j] = true;
    }
  }
  return primos;
}
struct Link {
  long long from, to, cost;
};
struct Node {
  bool visitado = false;
  bool cor = false;
  vector<long long> in, out;
};
bool d[200][200];
int main() {
  ios::sync_with_stdio(false);
  cin.tie(0);
  cout.tie(0);
  long long n;
  cin >> n;
  vector<string> a(n);
  for (auto &x : a) cin >> x;
  for (long long i = 0; i < (long long)n; i++) {
    for (long long j = 0; j < (long long)n; j++) {
      if (not d[i][j] and a[i][j] == '#') {
        if (i >= n - 2 or j == 0 or j == n - 1) {
          puts("NO");
          return 0;
        }
        long long x = a[i][j] + a[i + 1][j - 1] + a[i + 1][j] +
                      a[i + 1][j + 1] + a[i + 2][j];
        if (x != 5 * '#') {
          puts("NO");
          return 0;
        }
        if (d[i + 1][j] or d[i + 1][j - 1] or d[i + 1][j + 1] or d[i + 2][j]) {
          puts("NO");
          return 0;
        }
        d[i][j] = d[i + 1][j - 1] = d[i + 1][j] = d[i + 1][j + 1] =
            d[i + 2][j] = true;
      }
    }
  }
  puts("YES");
}
