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>
#include <algorithm>
using namespace std;

int main(){
	int x;
	cin >> x;
	int ans = 1;
	for(int i=2; i*i<=x; i++){
		int prod = i;
		while(prod <= x){
			ans = max(ans, prod);
			prod *= i;
		}
	}
	cout << ans << endl;
	return 0;
}