#include <bits/stdc++.h>
using namespace std;
int main() {
  int n, m, n1, m1;
  cin >> n >> m >> n1 >> m1;
  if (n1 == n || m1 == m) {
    cout << abs(n - n1) * 2 + abs(m - m1) * 2 + 6;
  } else {
    cout << abs(n - n1) * 2 + abs(m - m1) * 2 + 4;
  }
}
