Match the colors of the graphs in this figure with the functions given below. Enter y for yellow, b for blue, r red, p for purple, and g for green, as appropriate.

$f(x) = x^3$
$f(x) = (x-1)^3$
$f(x) = (x+1)^3$
$f(x) = x^3-1$
$f(x) = x^3+1$