#include <bits/stdc++.h>
using namespace std;
#define MAX 100000001
int main() {
	int x,y,x2,y2;
	cin>>x>>y>>x2>>y2;
	if(x==y&&x2==y2&&x>x2)		cout<<x+1<<endl;
	else		cout<<max(x,y)<<endl;
	return 0;
}