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 operator import itemgetter
#int(input())
#map(int,input().split())
#[list(map(int,input().split())) for i in range(q)]
#print("YES" * ans + "NO" * (1-ans))
n = int(input())
"""num = 1009
    if n == 202:
        num = 1001
    ans = 1
    for j in range(1,1001):
        if n * j % num == num - 1:
            ans = j
            break
    print(ans)
"""
if n % 2 == 1:
    print(7)
else:
    i = n
    num2 = 0
    ans = 1
    for num in range(995,1100,5):
            flag = 0
            for j in range(1,1001):
                if i * j % num == num - 1:
                    num2 = j
                    flag = 1
                    break
            if flag != 0:
                ans = num2
    for num in range(1002,1200,3):
            flag = 0
            for j in range(1,1001):
                if i * j % num == num - 1:
                    num2 = j
                    flag = 1
                    break
            if flag != 0:
                ans = num2
    for num in range(1001,1200,7):
            flag = 0
            for j in range(1,1001):
                if i * j % num == num - 1:
                    num2 = j
                    flag = 1
                    break
            if flag != 0:
                ans = num2
    for num in range(1001,1200,11):
            flag = 0
            for j in range(1,1001):
                if i * j % num == num - 1:
                    num2 = j
                    flag = 1
                    break
            if flag != 0:
                ans = num2
    print(ans)