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(void)
{
	int x;

	cin >> x;
	int ans = 1;

	for (int i = 2; pow(i, 2) <= x; i++)
	{
		for(int j = 2; pow(i, j) <= x; j++)
		{
			if (ans < pow(i, j))
				ans = pow(i, j);
		}
	}
	cout << ans << endl;
}
