# -*- coding:utf-8 -*-
# http://yukicoder.me/problems/391
primes = [2]


def generate_primes(n):
    for i in range(primes[-1], n + 1):
        if is_prime(i):
            primes.append(i, generate=False)
    return primes

def is_prime(n, generate=True):
    # if generate:
    #     generate_primes(n)
    for p in filter(lambda x: x ** 2 <= n, primes):
        if i % p == 0:
            return False
    return True

if __name__ == '__main__':
    n = int(input())
    for i in range(n - 100, n + 101):
        if not is_prime(i):
            print(i)
            break