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 x;

int main(void)
{
	cin >> x;
	
	int ans = 1;
	for(int i = 2; i <= x; i++){
		int v = i*i;
		while(v <= x){
			ans = max(ans, v);
			v *= i;
		}
	}
	cout << ans << endl;
	return 0;
}