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 n,count=0;
	cin>>n;
	if(n==1){cout<<1<<endl;return 0;}
	for(int i=2;i*i<=n;i++){
		for(int j=2;pow(i,j)<=n;j++){
			if(count<pow(i,j))count=pow(i,j);
		}
	}
	cout<<count<<endl;
}	
