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=1;
for(int b=2;b<32;b++){
  for(int p=2;p<10;p++){
    int tmp=pow(b,p);
    if(tmp<=N){
      ans= max(ans,tmp);
    }
  }
}
cout<<ans<<endl;
}
