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:
limit = 20000
prime = [True for i in range(limit + 1)]
p = 2
while p * p <= limit:

    # If prime[p] is not changed, then it is a prime
    if prime[p]:

        # Update all multiples of p
        for i in range(p * 2, limit + 1, p):
            prime[i] = False
    p += 1

# Print all prime numbers
# for p in range(2, n):
#     if prime[p]:
#         print(p)

# print(len(prime))

n = int(input())

for m in range(1001):
    if not prime[n*m + 1]:
        print(m)
        break