#include <bits/stdc++.h>
using namespace std;
string v[109];
int n;
bool valid(int x, int y) {
  if (x >= n || y >= n || x < 0 || y < 0 || v[x][y] == '.') return false;
  return true;
}
void check(int x, int y) {
  if (!valid(x + 1, y) || !valid(x - 1, y) || !valid(x, y + 1) ||
      !valid(x, y - 1))
    return;
  v[x + 1][y] = '.';
  v[x - 1][y] = '.';
  v[x][y + 1] = '.';
  v[x][y - 1] = '.';
  v[x][y] = '.';
  return;
}
int main() {
  cin >> n;
  int c = 0;
  for (int i = 0; i < n; i++) {
    cin >> v[i];
    for (int j = 0; j < n; j++)
      if (v[i][j] == '#') c++;
  }
  if (c % 5 != 0) {
    cout << "NO";
    return 0;
  }
  for (int i = 0; i < n; i++) {
    for (int j = 0; j < n; j++) {
      if (v[i][j] == '#') {
        check(i, j);
      }
    }
  }
  for (int i = 0; i < n; i++) {
    for (int j = 0; j < n; j++) {
      if (v[i][j] == '#') {
        cout << "NO" << endl;
        return 0;
      }
    }
  }
  cout << "YES" << endl;
  return 0;
}
