Problem:
Euler's Phi Function

For given integer n, count the totatives of n, that is, the positive integers less than or equal to n that are relatively prime to n.

Input

n

An integer n (1 ≤ n ≤ 1000000000).

Output

The number of totatives in a line.

Sample Input 1

6

Sample Output 1

2

Sample Input 2

1000000

Sample Output 2

400000

Solution in Python3 (judge verdict: Time Limit Exceeded)

n=m=int(input())
i=2
while i<=n and m!=1:
    if m%i==0:
        n=n*(i-1)//i
        while m%i==0: m//=i
    i+=1
print(n)