Relatively Prime

Given a positive integer N, determine how many of the integers between 1 and N are co-prime with N.

Two numbers are co-prime if the only common positive factor of the two numbers is 1.

Input

The input will contain one integer N (0 < N < 1000).

Output

Print a single integer--the number of integers between 1 and N that are co-prime with N.

Samples

Input	Output
15	8

Input	Output
20	8