Stones in heaps
Source: All Russian Olympiad 2017,Day1,grade 10,P3
May 3, 2017
combinatorics
Problem Statement
There are 3 heaps with stones. Ilya and Kostya play next game. Every step they take one stone from some heap, but not from same, that was on previous step. They make his steps in turn, Ilya make first step. Player loses if can not make step. Who has winning strategy?