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 is_prime(number):
    result = True
    for x in range(2, number):
        if not number % x:
            result = False
            break
    return result


class CodeforcesTask755ASolution:
    def __init__(self):
        self.result = ''
        self.n = 0

    def read_input(self):
        self.n = int(input())

    def process_task(self):
        for m in range(1, 1000):
            if not is_prime(m*self.n + 1):
                self.result = str(m)
                break

    def get_result(self):
        return self.result


if __name__ == "__main__":
    Solution = CodeforcesTask755ASolution()
    Solution.read_input()
    Solution.process_task()
    print(Solution.get_result())