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;
signed main(){
  int n,a=0,b;
  cin>>n;
  for(int i=1;i<=n;i++){
    for(int j=2;j<=n+1;j++){
      b = pow(i,j);
      if(b<=n){
        a = max(a,b);
      }
    }
  }
  cout<<a<<"\n";
}
