Recall that the Fibonacci numbers $F(n)$ are defined by:
- $F(0) = 0$
- $F(1) = 1$
- $F(n) = F(n - 1) + F(n - 2)$ for $n \geq 2$.

Determine the last digit of $F(2006)$.

Let's think step by step and output the final answer within \boxed{}.
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