Find a conformal map w(z) of the right half-disk \{ \text{Re}(z), |z|<1 \} onto the upper half-plane that maps -i to 0, +i to \infty, and 0 to -1. What is w(1)?

The back of the book says that w=\frac{-(z+i)^2}{(z-i)^2}, w(1)=1. However, I still do not see how they get w=\frac{-(z+i)^2}{(z-i)^2}. For the second part we can plug in 1 to get 1 as the output. I just don't see how to get w=\frac{-(z+i)^2}{(z-i)^2}. Thanks in advance.