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;
	cin>>n;
	int ans=1;
	for(int i=2;i<=n;i++){
		for(int j=2;j<i;j++){
			int z=i;
			while(z%j==0) z/=j;
			if(z==1){
				ans=max(ans,i);
			}
		}
	}
	cout<<ans;
}