And let's say, I should make the number line a little bit bigger. So there we go. Let's utilize the screen space. And so if this is zero, this is negative one, this is negative two, this is positive one, this is positive two, we know that at x equals negative one and x equals one, our second derivative is equal to zero. So let's think about what's happening in between those places to see if our second derivative is positive or negative. And from that, we'll be able to say where it's concave upward or concave downward. So on this first interval right over here, so this is the interval from, this is the interval where we're going from negative infinity to negative one.