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;
	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;
}
