Solution of 23rd problem in 08/2016 format from VK's Informatics_100 News Wire as of 14/09/2019

Original code

Consider a bit more complicated system like below.
I believe it's understandable that handle two variables
case is significantly easier.

((x1=>y1)=>z1) =>((x2≡y2)≡z2)=1
((x2=>y2)=>z2) =>((x3≡y3)≡z3)=1
((x3=>y3)=>z3) =>((x4≡y4)≡z4)=1
((x4=>y4)=>z4) =>((x5≡y5)≡z5)=1
((x5=>y5)=>z5) =>((x6≡y6)≡z6)=1

Fork 08/2016 diagram

Polyakov's control