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:
from math import sqrt   

def simple(a):
    if (a == 1 or a == 2 or a == 3):
        return (True)
    end = int(sqrt(a))
    for i in range(2,end+1):
        if (a%i == 0):
            return (False)
    return (True)

def myf(n):
    
    #Выведите такое m, что n·m + 1 не является простым.
    
    # если число нечетное, то умножаем на 1 и прибавляем 1. Тогда получится четное число. Теорема опровергнута.
    if (n == 1):
        return 5
    elif (n == 2):
        return 4
    elif (n%2 == 1):
        return 1
    else:
        # n - четное
        cont = True
        a = 1
        while (cont):
            test_number = n*a + 1
            if (simple(test_number) == False):
                cont = False
            else:
                a +=1
        return a
n = int(input())    
print (myf(n))