#include <iostream>
using namespace std;

int main(){
	int x, y, x2, y2;
	cin >> x >> y >> x2 >> y2;
	int res = max(x, y);
	if(x == y && x2 == y2 && x2 < x){
		++res;
	}
	cout << res << endl;
	return 0;
}