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 <iostream>
#include <math.h>
using namespace std;

int main(void){
    int x,ans=1;
    cin>>x;
    for(int i=2;i<=sqrt(x);i++){
        for(int j=i;j<=x;j*=i){
            ans=max(ans, j);
        }
    }
    cout<<ans<<endl;
}