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 <iostream>
#include <algorithm>

using namespace std;

int main()
{
	int X; 
	cin >> X;

	int ans = 1;

	for (int b = 2; b * b <= X; ++b) {
		for (int y = b; y <= X; y *= b) {
			ans = max(ans, y);
		}
	}

	cout << ans << endl;
}
