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;
	int maxv = 1;
	cin >> X;

	for ( int i = 2; i <= X; i++ ) {
		int g = i * i;
		while ( g <= X ) {
			maxv = max(maxv , g);
			g *= i;
		}
	}

	cout << maxv << endl;

	return (0);
}
