#include <bits/stdc++.h>
using namespace std;
int main() {
  int x1, y1, x2, y2 = 0;
  cin >> x1 >> y1;
  cin >> x2 >> y2;
  if (x2 == x1) {
    x2 += 2;
  } else if (x2 > x1) {
    x2 += 1;
  } else {
    x2 -= 1;
  }
  if (y2 == y1) {
    y2 += 2;
  } else if (y2 > y1) {
    y2 += 1;
  } else {
    y2 -= 1;
  }
  cout << 2 * (abs(x1 - x2) + abs(y1 - y2)) << endl;
}
