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 time
# from collections import defaultdict,deque
# from sys import stdin,stdout
# from bisect import bisect_left,bisect_right
# factory=defaultdict(lambda:False)
# n,m,k=map(int,input().split())
# graph=defaultdict(lambda:[])
# edgeval=defaultdict(lambda:math.inf)
# for _ in range(m):
#     u,v,l=map(int,input().split())
#     if(u>v):
#         u,v=v,u
#     graph[u].append(v)
#     graph[v].append(u)
#     edgeval[str(u)+" "+str(v)]=min(edgeval[str(u)+" "+str(v)],l)
# a=list(map(int,input().split()))
# for i in a:
#     factory[i]=True
# ans=math.inf
# # print(graph)
# for i in a:
#     for j in graph[i]:
#         if(not factory[j]):
#             if(i<=j):
#                 ans=min(ans,edgeval[str(i)+" "+str(j)])
#             else:
#                 ans=min(ans,edgeval[str(j)+" "+str(i)])
# if(ans is math.inf):
#     print(-1)
# else:
#     print(ans)

n=int(input())
if(n==1):
    print(3)
elif(n==2):
    print(4)
else:
    print(n-2)