#include <bits/stdc++.h>
using namespace std;
int ax, ay, bx, by;
int main() {
  while (scanf("%d %d", &ax, &ay) != EOF) {
    scanf("%d %d", &bx, &by);
    int h = max(2, abs(ax - bx) + 1), v = max(2, abs(ay - by) + 1);
    printf("%d\n", 2 * (h + v));
  }
  return 0;
}
