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 = [2,3,5,7,11,13,17,19]
def GenPrime(maxV:int,start=21):
    for x in range(start, maxV, 2):
        isprime = True
        for v in prime:
            if x % v == 0:
                isprime = False
                break
        if isprime: prime.append(x)
def IsPrime(k:int)->bool:
    for x in prime:
        if k == x: return True
        if k % x == 0: return False
    return True
n = int(input())
GenPrime(1000)
m = 1
while IsPrime(m*n + 1): m += 1
print(m)