#include <iostream>
#include <algorithm>
using namespace std;
int main(void){
    int x,y,x2,y2;
    cin>>x>>y>>x2>>y2;
    if(x==y && x2==y2 && 0<x2 && x2<x) cout<<max(x,y)+1<<endl;
    else cout<<max(x,y)<<endl;
    return 0;
}