#include <bits/stdc++.h>
using namespace std;
int main() {
  int x1, y1, x2, y2;
  cin >> x1 >> y1 >> x2 >> y2;
  if (x1 == x2 && y1 == y2)
    cout << 10 << endl;
  else if (x1 == x2 || y1 == y2)
    cout << (abs(x1 - x2) + abs(y1 - y2) + 1) * 2 + 4 << endl;
  else
    cout << (abs(x1 - x2) + abs(y1 - y2) + 2) * 2 << endl;
  return 0;
}
