Hey pranay.

Being co-prime to an integer means the gcd(a,b) = 1.

But in terms of the totient function, this means that totient(a,b) = totient(a)*totient(b) (which is on the first page of the wiki).

So you know how many numbers up to n-1 are co-prime by using totient and you also have a condition for when two numbers are co-prime. Can you modify this to get an expression to "remove" the specific numbers of integers that are co-prime but equal or larger than x?