#include "bits/stdc++.h"
using namespace std;
#define ll long long int
#define rep(i,n) for( int i = 0; i < n; i++ )
#define rrep(i,n) for( int i = n; i >= 0; i-- )
#define REP(i,s,t) for( int i = s; i <= t; i++ )
#define RREP(i,s,t) for( int i = s; i >= t; i-- )
#define dump(x)  cerr << #x << " = " << (x) << endl;
#define INF 2000000000
#define mod 1000000007
#define INF2 1000000000000000000


int main(void)
{
    cin.tie(0);
    ios::sync_with_stdio(false);
	int x, y;
	cin >> x >> y;
	int x2, y2;
	cin >> x2 >> y2;
	if (x == y && x2 == y2 && x2 < x) {
		cout << x + 1 << endl; 
	}
	else {
		cout << max(x, y) << endl;
	}

    return 0;
}