#include <iostream>
#include <algorithm>
#include <stdlib.h>
#include <string>
#include <queue>
using namespace std;


int main() {
int gx,gy,jy,jx;
cin>>gx>>gy;
cin>>jx>>jy;

int ans=max(gx,gy);

if(gx==gy && jx==jy) ans++;

cout<<ans<<endl;




return 0;
}