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
import sys
#####sorting a dictionary by the values#####
def dict_sort(ans):
    ans=sorted(ans.items(),reverse=True,key=lambda kv:(kv[1]))
##### naive method for testing prime or not O(n^.5)#####
def is_prime(n):
    if n==1:
        return 0
    for i in range(2,int(math.sqrt(n))+1):
        if n%i==0:
            return False
    return True
#####swap function#####
def swap(a,b):
    temp=a
    a=b
    b=temp
    return a,b
#####Primes till Nth O(n)#####
def seive_primes(n):
    flag=[0]*(n+10)
    flag[1]=flag[0]=1
    i=2
    while i*i<=n+1:
        if flag[i]==0:
            j=i*i
            while j<=n+1:
                flag[j]=1
                j+=i
        i+=1
    return flag
#####greatest common divisor of two numbers#####
def gcd(a,b):
    if b==0:
        return a
    return gcd(b,a%b)
#####least common multiplyer of two numbers#####
def lcm(a,b):
    return (a*b)//gcd(a,b)
#####function that return all the letters#####
def alphabates():
    return "abcdefghijklmnopqrstuvwxyz"
#####binary search O(logN)#####
def binary_search(ls,n,flag):
    low=0
    hi=n-1
    while(low<=hi):
        mid=(low+hi)//2
        if ls[mid]==flag:
            return mid
        elif ls[mid]>flag:
            hi=mid-1
        else:
            low=mid+1
    return -1
#####quadratic#####
def qdrt(x,a,b,c):
    return a*x*x+b*x+c
#####taking an array/list as input#####
def inp():
    ls=list(map(int,input().split()))
    return ls
#####taking multiple inputs#####
def mult_inp():
    return map(int,input().split())
#####Main function starts from here#####
for _ in range(1):
    n=int(input())
    if n==1:
        print(3)
    elif n==2:
        print(4)
    else:
        print(n-2)