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<iostream>
using namespace std;

int main(){
	int x;
	int max = 1;
	int tmp;
	cin >> x;
	for(int i=2; i< x; i++){
		tmp = i * i;
		while(tmp <= x){
			if(tmp > max) max = tmp;
			tmp *= i;
		}
	}
	cout << max;
}
