Lets play game logic

kathuria · September 30, 2018, 5:03pm

i am unable to figure out the logic behind this ques. somebody please help
ques link https://hack.codingblocks.com/contests/c/528/729

abhishek_trigunait · September 30, 2018, 5:28pm

For a given integer x, you need to find the number of pairs <a,b> such that gcd(a,b)=1. So, you need to find the number of pairs <a, x!/a> such that a ϵ {factors of x!}.