#include <bits/stdc++.h>
using namespace std;
int main() {
  int x1, x2, y1, y2, dx, dy, ans;
  cin >> x1 >> y1 >> x2 >> y2;
  dx = abs(x2 - x1);
  dy = abs(y2 - y1);
  if (dx == 0 || dy == 0) {
    if (dx == 0) {
      ans = (((dy - 1) * 2) + 8);
    } else
      ans = (((dx - 1) * 2) + 8);
  } else {
    ans = ((dx + dy + 2) * 2);
  }
  cout << ans;
  return 0;
}
