CF588B.Duff in Love

Duff is in love with lovely numbers! A positive integer x is called lovely if and only if there is no such positive integer a > 1 such that _a_2 is a divisor of x.

Malek has a number store! In his store, he has only divisors of positive integer n (and he has all of them). As a birthday present, Malek wants to give her a lovely number from his store. He wants this number to be as big as possible.

Malek always had issues in math, so he asked for your help. Please tell him what is the biggest lovely number in his store.

达芙爱上了“可爱的数”！一个正整数 $x$ 被称为可爱的，当且仅当不存在某个大于 $1$ 的正整数 $a$，使得 $a^2$ 整除 $x$。

马莱克拥有一家数字商店！在他的商店中，只出售某个正整数 $n$ 的所有正因数（且所有因数都齐全）。作为生日礼物，马莱克想从他的商店中送给达芙一个可爱的数。他希望这个数尽可能大。

马莱克在数学上一直不太在行，因此向你求助。请告诉他：他的商店中最大的可爱的数是多少？

The first and only line of input contains one integer, n (1 ≤ n ≤ 1012).

输入仅包含一行，其中有一个整数 $n$（$1 \leq n \leq 10^{12}$）。

Print the answer in one line.

在一行中输出答案。

In first sample case, there are numbers 1, 2, 5 and 10 in the shop. 10 isn't divisible by any perfect square, so 10 is lovely.

In second sample case, there are numbers 1, 2, 3, 4, 6 and 12 in the shop. 12 is divisible by 4 = 22, so 12 is not lovely, while 6 is indeed lovely.

在第一个样例中，商店中有数字 1、2、5 和 10。10 不能被任何完全平方数整除，因此 10 是“可爱的”。

在第二个样例中，商店中有数字 1、2、3、4、6 和 12。12 能被 $4 = 2^2$ 整除，因此 12 不是“可爱的”，而 6 确实是“可爱的”。