#include<cstdio>
#include<iostream>
#include<algorithm>
#include<string>
#include<queue>
#include<vector>
#include<functional>
#include<cmath>
#include<map>
#include<stack>
#include<set>
#include<numeric>
#include<limits>

using namespace std;
typedef long long ll;
typedef pair<int, int> pi;
typedef pair<ll, ll> pl;
typedef pair<ll, string> pls;

int main()
{
	ll x, y, x2, y2;
	cin >> x >> y >> x2 >> y2;
	
	ll ans = max(x, y);
	if ((x == y) && (x2 == y2)) ans++;
	cout << ans << endl;

	return 0;
}