#include <bits/stdc++.h>
using namespace std;
set<string> str;
vector<char> s1, s2;
char S1[1000000], S2[1000000];
int a, b, c, d;
int main() {
  scanf("%d %d", &a, &b);
  scanf("%d %d", &c, &d);
  int x = max(abs(c - a) + 1, 2);
  int y = max(abs(d - b) + 1, 2);
  printf("%d\n", 2 * (x + y));
  return 0;
}
