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 SieveOfEratosthenes(n): 
    prime = [i for i in range(n+1)] 
    p = 2
    while (p * p <= n): 
        if (prime[p]!=0): 
            for i in range(p * p, n+1, p): 
                prime[i] = 0
        p += 1
    return prime
def sol():
    n=int(input())
    A=SieveOfEratosthenes(10000)
    m=0
    while(True):
        m+=1
        if(A[n*m+1]==0):
            break
    print(m)
if(__name__=='__main__'):
    sol()
    #SieveOfEratosthenes(1000000)