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<cstdio>
int main()
{
	int n,ans=1;scanf("%d",&n);
	for(int i=2;i<35;i++)
	{
		int x=i*i;if(x>n) break;
		while(x*i<=n) x*=i;
		if(x>ans) ans=x;
	}
	printf("%d\n",ans);
	return 0;
}