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 X;
  cin>>X;
  int bp_max=1;
  for(int p=1;p<=X;++p){
    for(int b=2;b<=X;++b){
      int power=pow(p,b);
      if(power>X)break;
      bp_max=max(bp_max,power);
    }
  }
  cout<<bp_max<<endl;
}
