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 n=0;
	for(int i=1;i<=X;i++){
		int x=i;
		for(int j=1;j<=X;j++){
			x=x*i;
			if(x<=X)n=max(n,x);
		}
	}cout<<n<<endl;
				
				
}
