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>
#include<cmath>
using namespace std;
int main()
{
	int x,n;
	cin>>x;
	if(x==1) {cout<<1;return 0;}
	for(int i=2;i*i<=x;i++)
	for(int j=1;pow(i,j)<=x;j++)
	{
		if((x-pow(i,j))<(x-n)) n=pow(i,j);
	}
	cout<<n;
}