Let [math]x=R[/math] and [math]p[/math] be the discrete metric on [math]X[/math] defined by [math]p(x,y) = 8[/math] if [math]x[/math] is not equal to [math]y[/math] and [math]0[/math], if [math]x=y[/math]. What is [math]\text{B}_0\text{(-1)}[/math]?