A = 1 x 2/2 x 2 x 2 x 3/3 x 3 x 3 x 4/4 x 4 x 4 x 5/5 x 5 x ............x 2012 x 2013/ 2013 x 2013B = 2012 x 2013 - 2012 x 2012/2012 x 2011 + 2012 x 2
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