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:
"""# -*- coding: utf-8 -*-

Created on Sun Jun  2 15:21:54 2019

@author: avina


n = int(input())
l = input().split()
l = [(int(l[i]), i+1) for i in range(n)]
l.sort(key=lambda x:x[0])

for i in range(n//2):
    print(l[i][1],l[n-i-1][1])
"""
def  p(n):
    c=int(n**.5)+2
    d=0
    for i in range(2,c):
        if n%i==0:
            d=1
            break
    return d
        
        
        
        
x=int(input())
if x==1:
    print(3)
    exit(0)
if x==2:
    print(4)
    exit(0)
for i in range(1,100*x+1):
    cp=(x*i)+1
    if p(cp)==1:
        print(i)
        exit(0)