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 a,b=0;
  cin>>a;
  if(a==1){cout<<1<<endl;}
  else{
  for(int i=2;i<=sqrt(a);i++){
    int j=i;
    while(j*i<=a){j*=i;}
    
    if(b<j&&j!=i){b=j;}}
  cout<<b<<endl;
  }
}

