#include <bits/stdc++.h>
using namespace std;
int main() {
  int n, m;
  cin >> n >> m;
  int a[n][m];
  for (int i = 0; i < n; ++i)
    for (int j = 0; j < m; ++j) cin >> a[i][j];
  int gcount = 4;
  for (int i = 0; i < n; ++i) {
    for (int j = 0; j < m; ++j) {
      if (a[i][j] == 1) {
        if (i == 0 || i == n - 1 || j == 0 || j == m - 1) {
          cout << 2;
          return 0;
        }
      }
    }
  }
  cout << gcount;
}
