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For \(n > 2\), the \(n\)th Fibonacci number \(F(n)\) is the sum of \(F(n-1)\) and \(F(n-2)\), and the first and second Fibonacci numbers are 1. I.e.,

\[ \begin{align} F(1) & = 1 \\ F(2) & = 1 \\ F(n) & = F(n-1) + F(n-2) \end{align} \]

Write a function to compute the \(n\)th Fibonacci number.

Examples

>>> map fibonacci [1..10]
[1,1,2,3,5,8,13,21,34,55]