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;
typedef long long ll;

 int main() {
	 int X;
	 cin >> X;
	 int ans = 1;
	 for (int i = 2; i*i <= X; i++) {
		 int Y = i;
		 while (Y*i <= X) Y *= i;
		 ans = max(ans, Y);
	 }
	 cout << ans << endl;
}