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:
prime = []
numberlist = []
for i in range(2, 1001):
	numberlist.append(i)
while numberlist[0] < 32:
	now = numberlist.pop(0)
	prime.append(now)
	newnumberlist = []
	for i in range(0, len(numberlist)):
		if numberlist[i] % now != 0:
			newnumberlist.append(numberlist[i])
	numberlist = newnumberlist
prime = prime + newnumberlist

N = int(input())
flag = False
for i in range(1, 1001):
	X = N*i+1
	if X <= 1000:
		if X not in prime:
			print(i)
			break
	else:
		flag = False
		for j in range(0, len(prime)):
			if X % prime[j] == 0:
				flag = True
				print(i)
				break
		if flag:
			break