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 ans = 1;
	for (int i = 2; i * i <= X; i++) {
		int j = 2;
		while (true) {
			int k = pow(i, j);
			if (k > X) break;

			ans = max(ans, k);
			j++;
		}
	}
	cout << ans;
}
