You are given a positive integer X. Find the largest perfect power that is at most X. Here, a perfect power is an integer that can be represented as b^p, where b is an integer not less than 1 and p is an integer not less than 2.

Constraints

* 1 ≤ X ≤ 1000
* X is an integer.

Input

Input is given from Standard Input in the following format:


X


Output

Print the largest perfect power that is at most X.

Examples

Input

10


Output

9


Input

1


Output

1


Input

999


Output

961
#include <bits/stdc++.h>

using namespace std;

int main()
{
	int x;
	cin >> x;
	int pp = 1;
	for (int i = 2; i <= (int)sqrt(x); i++)
	{
		int power = (int)(log2(x)/log2(i));
		pp = max(pp, (int)pow(i, power));
	}
	cout << pp << endl;
	return 0;
}
