# -*- coding: utf-8 -*-
"""
No.312 置換処理
https://yukicoder.me/problems/no/312

"""
import sys
from sys import stdin
input = stdin.readline


def calc_divisor(N):
    # 約数の列挙
    divisors = set()
    for i in range(1, int(N**0.5)+1):
        if N % i == 0:
            divisors.add(i)
            divisors.add(N // i)
    return divisors


def solve(N):
    d = calc_divisor(N)
    d.discard(1)
    d.discard(2)
    return min(d)


def main(args):
    N = int(input())
    ans = solve(N)
    print(ans)


if __name__ == '__main__':
    main(sys.argv[1:])