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>

using namespace std;


int main()
{
	int X;
	cin >> X;
	int m = 1;
	for (int i = 2; i < 32; i++) {
		int y = i * i;
		for (;y <= X; y *= i) {
			if (m < y) m = y;
		}
	}
	cout << m << endl;
	return 0;
}