RF interview question

Matching problem:

Refer the attached figure, when the Zs matched to ZL, that is Zout=ZL*, prove that Zin=Zs*.

Gamma_Load = 0 => VSWR_Load = 1.
Since the MN is lossless => VSWR_Source = VSWR_Load = 1
Then Gamma_Source = 0 => Zin = Zs*