#include <bits/stdc++.h>
using namespace std;
int xs[8] = {1, 1, 1, 0, 0, -1, -1, -1};
int ys[8] = {-1, 0, 1, -1, 1, -1, 0, 1};
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(0);
  int x1, y1, x2, y2;
  cin >> x1 >> y1;
  cin >> x2 >> y2;
  int nx, ny;
  int mV = INT_MAX;
  for (int i = 0; i < 8; i++) {
    nx = xs[i] + x2;
    ny = ys[i] + y2;
    mV = min(abs(nx - x1) + abs(ny - y1), mV);
  }
  cout << 2 * mV + 8 << '\n';
}
