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 math

n=int(input())
#ko=math.ceil(math.sqrt(n)) 
ko=1000*1000+1
#arr_size=int(ko//2)

arrnum = [False for arrnum in range(0,ko)]
#print(arrnum)

for i in range(2,ko):
    if not(arrnum[i]):
        for j in range(i+i,ko,i):
            arrnum[j]=True
            #print('arrnum['+str(i)+","+str(j)+']'+"="+str(arrnum[j]))


#print(ko)

# for i in range(2,ko):
#     if not(arrnum[i]):
#         print(i)
m=1

while not(arrnum[n*m+1]):
    m+=1
    
print(m)