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<cmath>

using namespace std;

int main() {
	int N, M = 1, i, j;
	cin >> N;
	for (i = 9; i-1 ; i--) {
		for (j = 32; j; j--) {
			if (M <=pow(j, i)&&pow(j,i)<=N) M = pow(j,i);
		}
	}
	cout << M << endl;
}