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 "cmath"

using namespace std;

int main()
{
	int x,a=1,b=1,max=1;
	cin >> x;
	for (a = 2;a<=sqrt(x); a++) {
		for (b = 2;pow(a,b)<=x; b++) {
			if (pow(a, b) > max)max = pow(a, b);
		}
	}
	cout << max << endl;
	return 0;
}

