#include <bits/stdc++.h>
using namespace std;
void solve() {
  int x1, y1, x2, y2;
  cin >> x1 >> y1 >> x2 >> y2;
  if (x1 == x2 && y1 == y2) {
    cout << "10";
    return;
  }
  if (x1 == x2) {
    cout << 2 * (abs(y2 - y1) + 1) + 4;
    return;
  }
  if (y1 == y2) {
    cout << 2 * (abs(x2 - x1) + 1) + 4;
    return;
  }
  cout << 2 * (abs(x2 - x1) + abs(y2 - y1) + 2);
}
int main() {
  solve();
  return 0;
}
