#include <bits/stdc++.h>
using namespace std;
#define rep(i,n) for(int i=0;i<(n);i++)
#define MP make_pair
#define PB push_back
typedef long long ll;
int main(){
	ll x,y,xx,yy,ans;
	cin>>x>>y>>xx>>yy;
	if(x==y&&xx==yy){
		cout<<x+2<<endl;
	}else cout<<min(x,y)+abs(x-y)<<endl;
}