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:
#!/usr/bin/env python3

"""
factors = sieve()
factors[9] = 3
factors[10] = 5
factors[11] = -1

n       time    memory
10^7    300ms   140 MB
"""
def sieve(n=10**7):
    s = [-1] * n
    for i in range(2, int(n**0.5)+1):
        if s[i] != -1: continue
        for j in range(i, n, i): 
            if j > i: s[j] = i
    return s

def primes(n=10**7):
    factors = sieve(n)
    return [i for i, e in enumerate(factors) if e == -1 and i >= 2]

PRIMES = set(primes(10**6))
n = int(input())

for m in range(1, 1000):
    if n*m+1 not in PRIMES:
        print(m)
        exit()