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>
using namespace std;
int main(){
    int i,j,x,k;
    cin >> x;
    k=1;
    for(i=2;i*i<=x;i++)
    {
        for(j=i*i;j<=x;j*=i)
            if(j>k)
            	k=j;
    }
   
    cout << k << endl;
    return 0;
}
