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>
#include<algorithm>
int main()
{
	int x,ans=0;
	scanf("%d",&x);
	for(int i=1;i<=1000;i++)
		for(int j=2;j<=1000;j++)
		{
			int t=pow(i,j);
			if(t>x)
				break;
			if(ans<t)
				ans=t;
		}
	printf("%d\n",ans);
	return 0;
}
