import java.util.*;

public class _11943 {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int A = sc.nextInt(), B = sc.nextInt(), C = sc.nextInt(), D = sc.nextInt();
        sc.close();

        System.out.println(Math.min(A+D, B+C));
    }
}