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 ans=1, N;   
    cin >> N;
    for(int i=1;i<=1000 ; i++){
	for(int j=2; j<=1000; j++){
	    if((int)pow(i, j) <=N)
		ans = max(ans, (int)pow(i, j));
	}
    }
    cout << ans<< endl;
}
