#include <bits/stdc++.h>
#define rep(i,n) for(int i=0;i<(n);++i)
#define all(a) (a).begin(),(a).end()
#define dunk(a) cout << (a) << endl
using namespace std;
typedef long long ll;

signed int main() {
	ios::sync_with_stdio(false);
	cin.tie(0);
	int x, y, x2, y2;
	cin >> x >> y >> x2 >> y2;

	if (x != y) {
		dunk(max(x, y));
		return 0;
	}

	if (x2 < x && x2 == y2) {
		dunk(x + 1);
		return 0;
	}

	dunk(x);

	return 0;
}