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

int main(){
int x,n=1;
cin >> x;
for (int i=2;i<=x;i++){
for (int j=2;j<=x;j++){
if (n<=pow(i,j) && x>=pow(i,j)) n=pow(i,j);
}
}
cout << n << endl;
}