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=1;
  int exp;
  
  for(int i=2; i*i<=X; i++){
    exp=i*i;
    while(exp<=X){
      if(exp>ans)ans=exp;
      exp*=i;
    }
  }
  
  cout << ans << endl;
}