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,aa,ans;
  cin>>x;
  if(x<4)cout<<1<<endl;
  else{
  for(int i=2;i*i<x;i++){
    aa=i*i;
    for(;aa<=x;){
      ans=max(ans,aa);
      aa*=i;
    }
  }
  cout<<ans<<endl;
}
}
