#include <bits/stdc++.h>
using namespace std;
int main() {
  int a, b, aa, bb;
  cin >> a >> b;
  a += 100;
  b += 100;
  cin >> aa >> bb;
  aa += 100;
  bb += 100;
  if (aa != a && bb != b) {
    int tmp = (abs(a - aa));
    int tmp2 = (abs(b - bb));
    cout << 2 * abs(tmp2 + tmp) + 4;
  } else
    cout << max(8, (6 + (abs(a - aa) + abs(b - bb)) * 2));
  return 0;
}
