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,s=0,k=0,l=1;
	cin>>x;
	for( int i=sqrt(x);i>=1;i--){
		for( int j=2;j<=x;j++){
			s=j;
			k=1;	
			while(s!=0){
				s--;
				k=k*i;
				if(k<=x) l=max(l,k);
			}
		}
	}
	cout<<l;
	return 0;
}
