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Game Theory 7.0/10

Three Heaps, Three Subtractions

Three heaps contain 38, 53 and 71 stones. Two players alternate; a move picks one heap and removes exactly 2, 5 or 6 stones from it (a heap with fewer stones than the amount cannot be used for that amount). A player who cannot move loses. Two moves are different if they use different heaps or different amounts. How many first moves put the opponent in a losing position? Give an integer.

Related problems & prerequisites

Worth solving first

Source: Sprague-Grundy theory applied to a subtraction game; written for AxiomIQ.