#include <iostream>
#include <vector>
#include <string>
#include <algorithm>
using namespace std;

int main() {
	int x1, y1, x2, y2;
	cin >> x1 >> y1 >> x2 >> y2;
	int ans = max(x1, y1);
	if(x1 == y1 && x2 == y2 && x1 > x2) {
		ans++;
	}
	cout << ans << endl;
}