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 ans=1;
	for(int j=2;j<=x;j++){
		int ret=j;
		while(ret<=x){
			ret*=j;
			if(ret<=x){
				ans=max(ans,ret);
			}
		}
	}
	cout<<ans<<endl;
	return 0;
}