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