#coding: UTF-8

import sys
import re
import itertools
from math import sqrt
from collections import deque

### defs ###
def isprime(n):

	sq = sqrt(n)
	sq = int(sq) + 1
	for i in range(2,sq):
		if (n%i==0):
			return False

	return True

### main ###
N = int(sys.stdin.readline())

for n in range(N-100,N+101):
	if(isprime(n)==False):
		print(n)
		break