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 ans=0;
  for (int i=1;i<33;i++){
    for (int j=2;j<10;j++){
      int n=pow(i,j);
      if (n<=X && ans<n){
        ans=n;
      }
    }
  }
  cout<<ans<<endl;
}
      
