#include <bits/stdc++.h>
using namespace std;
int main() {
  int x1, x2, y1, y2;
  cin >> x1 >> y1;
  cin >> x2 >> y2;
  if (abs(x2 - x1) != 0 && abs(y2 - y1) != 0) {
    cout << 2 * (abs(x2 - x1) + abs(y2 - y1) + 2) << endl;
  } else {
    if (abs(x2 - x1) == 0) {
      cout << 2 * (3 + abs(y2 - y1)) << endl;
    } else {
      cout << 2 * (3 + abs(x2 - x1)) << endl;
    }
  }
  return 0;
}
