#include <bits/stdc++.h>
using namespace std;
int main() {
  int a, b, c, d;
  cin >> a >> b >> c >> d;
  int px, py;
  if (a > c) {
    px = c + 1;
  } else if (a < c) {
    px = c - 1;
  } else
    px = c;
  if (b > d) {
    py = d + 1;
  } else if (b < d) {
    py = d - 1;
  } else
    py = d;
  if (abs(a - c) < 2 && abs(b - d) < 2) {
    cout << 8 << endl;
    return 0;
  }
  int sum = 0;
  sum = abs(a - px) + abs(b - py);
  sum *= 2;
  sum += 8;
  cout << sum << endl;
  return 0;
}
