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 N;
	cin >> N;
	int num = 1, ans = 1;
	for (int i = 1; i <= N; i++) {
		for (int j = 2; j <= N; j++) {
			num = pow(i, j);
			if (N >= num) ans = max(num, ans);
		}
	}
	cout << ans << endl;
}
