#include <bits/stdc++.h>
using namespace std;
int n;
struct point {
  long long x, y;
  point(){};
  point(long long nx, long long ny) : x(nx), y(ny){};
  point operator-(point p) { return point(p.x - x, p.y - y); }
};
int main() {
  cin.tie(0);
  cout.tie(0);
  ios_base::sync_with_stdio(0);
  long long x1, y1, x2, y2;
  cin >> x1 >> y1 >> x2 >> y2;
  point s = point(x1, y1), f = point(x2, y2);
  point v = (s - f);
  long long fl = 0;
  if (x1 == x2 || y1 == y2) fl = 2;
  if (v.x >= 0 && v.y <= 0) {
    ++x2;
    --y2;
  } else if (v.x <= 0 && v.y <= 0) {
    --x2;
    --y2;
  } else if (v.x <= 0 && v.y >= 0) {
    --x2;
    ++y2;
  } else {
    ++x2;
    ++y2;
  }
  long long ans = 0;
  ans += abs(x2 - x1) * 2 + abs(y2 - y1) * 2;
  ans += fl;
  cout << ans << endl;
  return 0;
}
