#include <bits/stdc++.h>
using namespace std;
int main() {
  int x1, x2, y1, y2;
  scanf("%d%d%d%d", &x1, &y1, &x2, &y2);
  if (x1 == x2)
    printf("%d\n", 2 * (abs(y1 - y2) + 3));
  else if (y1 == y2)
    printf("%d\n", 2 * (abs(x1 - x2) + 3));
  else
    printf("%d\n", 2 * (abs(x1 - x2) + abs(y1 - y2) + 2));
  return 0;
}
