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 res = 1;
	for(int i = 2;i <= n; i++){
		int p = i*i;
		int pprev = 1;
		while(p<=n){
		 pprev = p;
		 p*=i;
		}
		if(pprev<=n) res = max(res,pprev);
	}
	cout<<res;
}