#include <atcoder/all> #include <bits/stdc++.h> using namespace std; using ll=long long; using ull=unsigned long long; #define rep(i,n) for(int i=0; i<(n); i++) int main(){ ll a,b,c,d; cin>>a>>b>>c>>d; if(a==c || b==d || abs(a-c)+abs(b-d)<=3) cout<<1<<endl; else cout<<2<<endl; return 0; }