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
sys.setrecursionlimit(10**6)

debug_mode = True if len(sys.argv) > 1 and sys.argv[1] == "-d" else False
if debug_mode:
    import os
    infile = open(os.path.abspath(__file__).replace(".py", ".in"))

    def input():
        return infile.readline()


# ==============================================================


def sieve(n):
    not_prime = set()
    primes = []
    for i in range(2, n + 1):
        if i not in not_prime:
            primes.append(i)
            for j in range(i * i, n + 1, i):
                not_prime.add(j)
    return primes


def main():
    primes = set(sieve(10**6))

    n = int(input().strip())
    for i in range(n, 10**6 + 2):
        if i in primes:
            continue
        if (i - 1) % n == 0 and (i - 1) // n >= 1:
            print((i - 1) // n)
            return


main()

# ==============================================================

if debug_mode:
    infile.close()