That would be a negative number. So right as x goes right above 0, this thing right here is negative. So as x is greater than 0, you will have your second derivative is going to be less than 0, your concave downwards, which makes sense because at some point we're going to be hitting a transition. Remember, we were concave downwards before we got to 2 thirds. So this is consistent. From 0 to 2 thirds, we are concave downwards. And then at 2 thirds, we become concave upwards.