# Random walks

Richard (aka Bob) is walking on a number line. He begins at $$0$$, and the $${i}^{th}$$ step's position, $${A}_{i}$$, is $${A}_{i-1}\pm1$$. (Both cases equally probable)

If $$K$$ is the average value of $${{A}_{100}}^{2}$$, input $$\sqrt{K}$$.

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