#include <stdio.h>

int main()
{
int a ,b ,c ,d;
scanf("%d %d %d %d",&a,&b,&c,&d);

if((a+b)%2 == 0 && (c+d)%d == 0 || (a+b)%2 == 1 && (c+d)%2 == 1)
printf("black\n");
if((a+b)%2 == 0 && (c+d)%2 == 1)
printf("white\n");
return 0;
}