#include <bits/stdc++.h>
using namespace std;
long long mod = 1e9 + 7;
long long gcd(long long a, long long b) {
  if (b == 0) return a;
  return gcd(b, a % b);
}
long long expo(long long base, long long pow) {
  long long ans = 1;
  while (pow != 0) {
    if (pow & 1 == 1) {
      ans = ans * base;
    }
    base *= base;
    pow /= 2;
  }
  return ans;
}
long long inv(long long x) { return expo(x, mod - 2); }
long long lt[1234][1234], rt[1234][1234], upper[1234][1234], lower[1234][1234];
int dist(int x1, int y1, int x2, int y2) { return abs(x1 - x2) + abs(y1 - y2); }
map<int, vector<int> > mp;
int main() {
  int x1, y1, x2, y2;
  cin >> x1 >> y1;
  cin >> x2 >> y2;
  int ans = 0;
  vector<int> vec;
  vec.push_back(dist(x1, y1, x2 - 1, y2 - 1));
  vec.push_back(dist(x1, y1, x2 + 1, y2 + 1));
  vec.push_back(dist(x1, y1, x2 - 1, y2 + 1));
  vec.push_back(dist(x1, y1, x2 + 1, y2 - 1));
  sort(vec.begin(), vec.end());
  ans = vec[0] + vec[1] + 6;
  cout << ans;
}
