#include <bits/stdc++.h>
using namespace std;
struct comp {
  bool operator()(int a, int b) { return a > b; }
};
int main() {
  int x1, y1, x2, y2;
  scanf("%d %d %d %d", &x1, &y1, &x2, &y2);
  int ans = 0;
  ans = max(ans, abs(x1 - (x2 - 1)) + abs(y1 - (y2 - 1)));
  ans = max(ans, abs(x1 - (x2 - 1)) + abs(y1 - (y2 + 1)));
  ans = max(ans, abs(x1 - (x2 + 1)) + abs(y1 - (y2 - 1)));
  ans = max(ans, abs(x1 - (x2 + 1)) + abs(y1 - (y2 + 1)));
  if (x1 == x2 || y1 == y2) ans++;
  printf("%d\n", ans * 2);
  return 0;
}
