def e(n):
	n,t=s(n,2,1)
	p=3
	while n>=p*p:
		if n%p<1:n,t=s(n,p,t)
		p+=2
	print t*(n-1)if n>1 else t
def s(n,p,t):
	c=1
	while n%p<1:n//=p;t*=p-c;c=0
	return n,t
while 1:
	try:e(input())
	except:break