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