#include <bits/stdc++.h>
using namespace std;
int abs(int x) {
  if (x < 0) {
    return -x;
  }
  return x;
}
int main() {
  int x1, x2, y1, y2;
  cin >> x1 >> y1 >> x2 >> y2;
  if (x1 != x2 && y1 != y2) {
    cout << (abs(x1 - x2) + abs(y1 - y2) + 2) * 2;
  } else {
    cout << (abs(x1 - x2) + abs(y1 - y2) + 3) * 2;
  }
}
