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 ans=1;
	
	for(int i=2;i<=sqrt(x);++i){
		int j=i;
		while(j<=x){
			if(j>ans)ans=j;
			j=j*i;
		}
	}
	printf("%d\n",ans);	
	
	return 0;
}
