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>
using namespace std;

int main(){
	int x,temp,top=1;

	cin >>x;
	if(x==1)cout<<1<<endl;
	else{
		for(int i=2;i<x;i++){
			for(temp=i*i;temp<=x;temp*=i){
				if(top<temp)top=temp;
			}
		}
		cout<<top<<endl;
	}
	return 0;
}