#include <bits/stdc++.h>
using namespace std;
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(0);
  long long x1, x2, y1, y2;
  cin >> x1 >> y1 >> x2 >> y2;
  if (x1 == x2) x2++;
  if (y1 == y2) y2++;
  long long answ = (abs(x1 - (x2 + 1)) + abs(y1 - (y2 + 1))) * 2;
  answ = max(answ, (abs(x1 - (x2 + 1)) + abs(y1 - (y2 - 1))) * 2);
  answ = max(answ, (abs(x1 - (x2 - 1)) + abs(y1 - (y2 - 1))) * 2);
  answ = max(answ, (abs(x1 - (x2 - 1)) + abs(y1 - (y2 + 1))) * 2);
  cout << max(answ, (long long)8) << endl;
  return 0;
}
