#include <bits/stdc++.h>
using namespace std;
int main() {
  int x1, x2, y1, y2;
  cin >> x1 >> y1 >> x2 >> y2;
  int ans;
  if (x1 == x2 || y2 == y1)
    ans = 2 * (abs(y1 - y2) + abs(x1 - x2)) + 6;
  else if (x1 > x2 && y1 > y2) {
    y2--;
    x2--;
    ans = abs(x2 - x1) + abs(y2 - y1);
    ans *= 2;
  } else if (x1 > x2 && y1 < y2) {
    y2++;
    x2--;
    ans = abs(x2 - x1) + abs(y2 - y1);
    ans *= 2;
  } else if (x1 < x2 && y1 > y2) {
    y2--;
    x2++;
    ans = abs(x2 - x1) + abs(y2 - y1);
    ans *= 2;
  } else {
    y2++;
    x2++;
    ans = abs(x2 - x1) + abs(y2 - y1);
    ans *= 2;
  }
  cout << ans;
  return 0;
}
