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 b = 2; b <= x; b++) {
		int v = b * b;
		while (v <= x) {
			ans = max(ans, v);
			v *= b;
		}

	}

	cout << ans << endl;

	return 0;
}