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>
using namespace std;
int main(){
	int x,count=1,ma=1;
	cin>>x;
	for(int i=2;i*i<=x;i++){
		while(count*i<=x){
			count*=i;
		}
		if(count>ma)ma=count;
		count=1;
	}
	cout<<ma<<endl;
}
