#include <bits/stdc++.h>
using namespace std;
int x[2][2];
int main() {
  for (int i = 0; i < 2; i++)
    for (int j = 0; j < 2; j++) scanf("%d", x[i] + j);
  printf("%d\n",
         (max(1, abs(x[0][0] - x[1][0])) + max(1, abs(x[0][1] - x[1][1])) + 2) *
             2);
  return 0;
}
