#include <bits/stdc++.h>
using namespace std;
vector<string> a(100);
long long n;
bool f() {
  long long i, j, x = -1, y = -1;
  for (i = 0; i < n; i++) {
    for (j = 0; j < n; j++)
      if (a[i][j] == '#') {
        x = i;
        y = j;
        j = n;
        i = n;
      }
  }
  if (y == 0 || y == n - 1) {
    cout << "NO";
    exit(0);
  }
  if (x == n - 1 || x == n - 2) {
    cout << "NO";
    exit(0);
  }
  if (x == -1 && y == -1) {
    cout << "YES";
    exit(0);
  }
  a[x][y] = '.';
  if (a[x + 1][y] == '.') {
    cout << "NO";
    exit(0);
  } else
    a[x + 1][y] = '.';
  if (a[x + 2][y] == '.') {
    cout << "NO";
    exit(0);
  } else
    a[x + 2][y] = '.';
  if (a[x + 1][y - 1] == '.') {
    cout << "NO";
    exit(0);
  } else
    a[x + 1][y - 1] = '.';
  if (a[x + 1][y + 1] == '.') {
    cout << "NO";
    exit(0);
  } else
    a[x + 1][y + 1] = '.';
  return true;
}
int main() {
  cin >> n;
  for (long long i = 0; i < n; i++) cin >> a[i];
  while (true) {
    f();
  }
  return 0;
}
