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 n;
  cin>>n;
  int ans=0;
  for(int i=2;i<32;i++){
    int t=i;
      while(i*t<=n){
        t*=i;
      }
    if(t>i){ans=max(ans,t);}
  }
  if(n==1){cout<<1;}
  else{cout<<ans;}
}
