∑s⊆S[gcd(s)>1]gcd(s)∣s∣\sum_{s \subseteq S} [gcd(s)>1] gcd(s)|s|∑s⊆S[gcd(s)>1]gcd(s)∣s∣
∣S∣<=5∗105|S|<=5*10^5∣S∣<=5∗105
