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 X;
	cin>>X;
	int res = 1;
	for(int b=2;b<=X;b++){
		int tmp = b;
		for(int p=2; tmp <= X; p++){
			tmp = tmp * b;
			if(tmp <= X) res = max(tmp, res);
		}
	}
	cout<<res<<endl;
}