CF671C Ultimate Weirdness of an Array

Yasin has an array $ a $ containing $ n $ integers. Yasin is a 5 year old, so he loves ultimate weird things. Yasin denotes weirdness of an array as maximum $ gcd(a_{i},a_{j}) $ value among all $ 1

The first line of the input contains a single integer $ n $ ( $ 1

Print a single line containing the value of ultimate weirdness of the array $ a $ .

Consider the first sample. - $ f(1,1) $ is equal to $ 3 $ . - $ f(2,2) $ is equal to $ 1 $ . - $ f(3,3) $ is equal to $ 2 $ . - $ f(1,2) $ , $ f(1,3) $ and $ f(2,3) $ are equal to $ 0 $ . Thus the answer is $ 3+0+0+1+0+2=6 $ .