import java.util.*;

public class Exercise108{
  public static void main (String[] args){

    Scanner sc = new Scanner(System.in);

    int ox = sc.nextInt();
    int oy = sc.nextInt();
    int hx = sc.nextInt();
    int hy = sc.nextInt();

    if(ox == oy && hx == hy && ox > hx){
      System.out.println(ox + 1);
    }else{
      System.out.println(Math.max(ox, oy));
    }
  }
}