#abc162c. [abc162_c]Sum of gcd of Tuples (Easy)

[abc162_c]Sum of gcd of Tuples (Easy)

a=1Kb=1Kc=1Kgcd(a,b,c)\sum_{a=1}^K\sum_{b=1}^K\sum_{c=1}^Kgcd(a,b,c)

的值。