#include <bits/stdc++.h>
using namespace std;
int X1, Y1, X2, Y2;
int main() {
  scanf("%d%d%d%d", &X1, &Y1, &X2, &Y2);
  if (X1 != X2 && Y1 != Y2)
    printf("%d\n", 2 * abs(X1 - X2) + 2 * abs(Y1 - Y2) + 4);
  else if (X1 == X2 && Y1 == Y2)
    printf("%d\n", 10);
  else if (X1 == X2)
    printf("%d\n", 2 * abs(Y1 - Y2) + 6);
  else if (Y1 == Y2)
    printf("%d\n", 2 * abs(X1 - X2) + 6);
  return 0;
}
