This problem is relatively straightforward -- we need to choose between three alternatives:

- If Farmer John drives directly from $a$ to $b$ without teleporting, he travels a distance of $|a - b|$.

- Farmer John could travel from $a$ to $x$, teleport to $y$, then travel to $b$, for a distance of $|a-x| + |b-y|$.

- Farmer John could travel from $a$ to $y$, teleport to $x$, then travel to $b$, for a distance of $|a-y| + |b-x|$.

Taking the smallest of these three yields the answer.

#include <iostream>
#include <algorithm>
using namespace std;
 
int main(void)
{
  int a, b, X[8], Y[8], x, y;
  cin >> a >> b;
  cin >> x >> y;
  int answer = abs(a-b); // no teleport
  answer = min(answer, abs(a-x) + abs(b-y));
  answer = min(answer, abs(a-y) + abs(b-x));
  cout << answer << "\n";
  return 0;
}