num = set()
try:
	while True:
		num.add(eval(input()))
except EOFError:
	max_num = max(num)
	is_primer = [True for _ in range(max_num+1)]
	for i in range(2,int(len(is_primer)/2)):
		if is_primer[i]:
			for j in range(i*2,len(is_primer),i):
				is_primer[j] = False
	count = 0
	for x in num:
		count = count + (1 if is_primer[x] else 0)
	print(count)