#include<iostream>
#include<algorithm>
#include<string>
#include<math.h>
#include<bitset>
#include <vector>
#include<bitset>
#include <iomanip>
#include <map>
#include <set>
#include <stack>
#include <deque>
#include <climits>
#include <queue>
using namespace std;

int main() {
	

	long long X, Y, X2, Y2;
	cin >> X >> Y >> X2 >> Y2;
	if (X != Y)cout << max(X, Y)<<endl;
	else {
		if (X2 == Y2)cout << max(X, Y) + 1<<endl;
		else cout << max(X, Y)<<endl;
	}


}