#include using namespace std; typedef pair PII; typedef long long LL; typedef unsigned long long ULL; template inline bool amax (T &a, const T &b) { if (a < b) { a = b; return 1; } return 0; } template inline bool amin (T &a, const T &b) { if (a > b) { a = b; return 1; } return 0; } template ostream& operator << (ostream &os, const vector &v) { os << "["; for (typename vector::const_iterator it = v.begin(); it != v.end(); it++) { os << (it != v.begin() ? ", " : "") << *it; } os << "]"; return os; } template ostream& operator << (ostream &os, const set &s) { os << "["; for (typename set::const_iterator it = s.begin(); it != s.end(); it++) { os << (it != s.begin() ? ", " : "") << *it; } os << "]"; return os; } template ostream& operator << (ostream &os, const map &m) { os << "{"; for (typename map::const_iterator it = m.begin(); it != m.end(); it++) { os << (it != m.begin() ? ", " : "") << it->first << ":" << it->second; } os << "}"; return os; } template ostream& operator << (ostream &os, const pair &p) { os << "(" << p.first << ", " << p.second << ")"; return os; } template inline Target lexical_cast (const Source &s) { Target t; stringstream ss; ss << s; ss >> t; return t; } //> v < ^ (clock wise) int dx[] = {1,0,-1,0}; int dy[] = {0,1,0,-1}; const int INFI = 1<<28; const long long int INFL = 1LL<<60; const double INFD = 1e+300; const float INFF = 1e+100; const double EPS = 1e-8; int main(){ cout.setf(ios::fixed); cout.precision(10); ios_base::sync_with_stdio(false); int x, y; cin >> x >> y; int x2, y2; cin >> x2 >> y2; int ans = abs(x-x2) + abs(y-y2); if ((x == 0 && x == x2) || (y==0 && y == y2)) { ans += 2; } cout << ans << endl; return 0; }