#include <bits/stdc++.h>
using namespace std;
int main() {
  int x1, y1, x2, y2;
  cin >> x1 >> y1 >> x2 >> y2;
  long long ans = 0;
  if (x1 == x2) {
    ans = abs(y2 - y1) - 1;
    cout << 2 * ans + 8;
    return 0;
  } else if (y1 == y2) {
    ans = abs(x2 - x1) - 1;
    cout << 2 * ans + 8;
    return 0;
  }
  x1 = x1 + 101;
  x2 = x2 + 101;
  y1 = y1 + 101;
  y2 = y2 + 101;
  ans = abs(x2 - x1) + abs(y2 - y1) + 2;
  cout << 2 * ans;
  return 0;
}
