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 <bits/stdc++.h>

using namespace std;

int main(){
	int i=2,j=2,X,m=1;
	cin >> X;
	while(i*i<X){
		if(X >= pow(i,j)){
			if(pow(i,j) >= m){
				m=pow(i,j);
			}
			j++;
		}else{
			i++;j=2;
		}
	}
	cout << m << endl;
	return 0;
}