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(){
	cin >> X;
	int ans = 1;
	for(int i=2;i<=35;i++){
		int now = i;
		for(int j=1;j<=10;j++){
			now *= i;
			if(now<=X) ans = max(ans,now);
			else break;
		}
	}
	cout << ans << endl;
}