# plz solve this one need the solution as urgent as posible

find the number of positive integers less than n that have a multiplicative inverse with respect to n

Constraints
N < 10^9

Input Format
The only line of the input is a single integer N which is divisible by no prime number larger than 13.

Output
One line containing an integer that gives the number of integers less than N that have a multiplicative inverse

All the numbers that are coprime to n have a multiplicative inverse - you don’t need to find the actual inverses. See Euler’s totient function \phi(n) to find out how many there are of these.

This function is multiplicative, and given the restriction on n, it is quick to assess whether each of the primes (2,3,5,7,11,13) divide n and adjust accordingly. For example if n is a power of 7 you just need to multiply by 6/7 to find \phi(n).

can you give me the full code in c++ plz

Not giving full code, but the process is: Starting with ans = n, we can check whether n is divisible by each of the above primes p in turn (e.g. if 0 == n%p) and if so set ans = (p-1) * (ans / p)