# A Snake-y Problem

A boy is standing at the foot of a flight of stairs. He has to reach to the $${ 9 }^\text{ th }$$ stair by taking steps of 1 or 2 only. He would have done it easily if there wasn't a snake of the $${7}^\text{th}$$ stair. What is the number of ways in which he can get to the $${9}^\text{th}$$ stair while avoiding the $${7}^\text{th}$$ stair?

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