#include <bits/stdc++.h>

using namespace std;

#define INF 2000000000
#define MOD 1000000007
typedef long long ll;
typedef pair<int, int> P;


int main()
{
	int x,y;
	int x2,y2;
	cin >> x >> y >> x2 >> y2;

	if (x==y&&x2==y2 &&(x<x2)) {
		cout << x+1 << "\n";
		return 0;
	}

	if (x==y) {
		cout << x << "\n";
		return 0;
	}

	int ret = max(x,y);
	cout << ret << "\n";

}