#include <bits/stdc++.h>
using namespace std;
using ll = long long;
const ll MOD = 1000000007;
const int dx[4] = {+1, 0, -1, 0};
const int dy[4] = {0, -1, 0, +1};
int main() {
  cin.tie(0);
  ios_base::sync_with_stdio(false);
}
