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() {
  double n,a;
  int s,max;
  max=0;
  cin>>n;
  for(double i=2;i<10;i++){
  a=pow(n,1/i);
  s=(10000*a+0.9)/10000;
  s=pow(s,i);
  if(s>max) max=s;  
  }
  cout<<max<<endl;  
}

  