Problem: PolandBall is a young, clever Ball. He is interested in prime numbers. He has stated a following hypothesis: "There exists such a positive integer n that for each positive integer m number n·m + 1 is a prime number".

Unfortunately, PolandBall is not experienced yet and doesn't know that his hypothesis is incorrect. Could you prove it wrong? Write a program that finds a counterexample for any n.

Input

The only number in the input is n (1 ≤ n ≤ 1000) — number from the PolandBall's hypothesis. 

Output

Output such m that n·m + 1 is not a prime number. Your answer will be considered correct if you output any suitable m such that 1 ≤ m ≤ 103. It is guaranteed the the answer exists.

Examples

Input

3


Output

1

Input

4


Output

2

Note

A prime number (or a prime) is a natural number greater than 1 that has no positive divisors other than 1 and itself.

For the first sample testcase, 3·1 + 1 = 4. We can output 1.

In the second sample testcase, 4·1 + 1 = 5. We cannot output 1 because 5 is prime. However, m = 2 is okay since 4·2 + 1 = 9, which is not a prime number.

Solution (in PYTHON3):

Solution:
def is_prime(adad):

	if adad==2:
		return True
	else:
		saquare = int(adad**(0.5))+1
		counter=2
		while(counter<saquare):
			if adad%counter!=0:
				counter+=1
			else:
				return False
		return True


vurudi_asli = int(input())

prime_check = True
zarib = 1
while(prime_check):

	vurudi = vurudi_asli*zarib + 1

	#Is vurudi prime??? if yes, then next zarib. if no, print the zarib
	#print(vurudi, is_prime(vurudi))
	if is_prime(vurudi) == True:
		zarib+=1
	else:
		print(zarib)
		prime_check = False