1 import java.util.Scanner; 2  3 public class Main{ 4     static int hl[][]=new int[20][20]; 5     static int sum=0; 6     static int blx,bly; 7     public static void unreach(int hx,int hy){ 8         hl[hx][hy]=hl[hx+1][hy+2]=hl[hx+2][hy+1]=hl[hx+2][hy-1]=hl[hx+1][hy-2]=hl[hx-1][hy-2] 9                 =hl[hx-2][hy-1]=hl[hx-2][hy+1]=hl[hx-1][hy+2]=1;10     }11     public static void count(int sx,int sy){12         if(hl[sx][sy]==1||sx>blx||sy>bly){13             return;14         }15         if(sx==blx&&sy==bly){16             sum++;17             return;18         }19         count(sx+1,sy);20         count(sx,sy+1);21     }22     public static void main(String args[]){23         Scanner sc=new Scanner(System.in);24         int bx,by,hx,hy;25         bx=sc.nextInt();26         by=sc.nextInt();27         blx=bx;28         bly=by;29         hx=sc.nextInt();30         hy=sc.nextInt();31         unreach(hx,hy);32         count(0,0);33         System.out.println(sum);34     }35 }