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:
import sys
from math import sqrt, floor, factorial
from collections import deque, Counter
inp = sys.stdin.readline
read = lambda: list(map(int, inp().strip().split()))

def is_prime(n):
	for i in range(2, int(sqrt(n))+1):
		if not n%i:
			return(False)
	return(True)

def solve():
	n = int(inp())
	if n % 2 == 1 and n != 1: print(1)
	else:
		for m in range(1, 10**3 +1):
			if not is_prime((n*m)+1):
				print(m); break

if __name__ == "__main__":
	solve()