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, ans = 0;
	cin >> x;
	for(int b = 1; b <= 40; b++) {
		for(int p = 2; p <= 10; p++) {
			if((int)pow(b, p) <= x) ans = max(ans, (int)pow(b, p));
		}
	}
	cout << ans << endl;
	return 0;
}