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 i = 2; i < X; i++)
	{
		for(int j = i*i; j <= X; j*=i)
		{	
			ans = max(ans, j);
		}
		
	}
	
	cout << ans << endl;
	
	return 0;
}