1/(n - 1) + (n - 2)/(n² - n) = 1/(n - 1) + (n - 2)/(n(n - 1)) =
= (n + (n - 2))/(n(n - 1)) = (2n - 2)/(n(n - 1)) = 2(n - 1)/n(n - 1)) =
= 2/n
