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;
  for(int i=2; i<=pow(x,0.5); i++){
    int p=i;
    while(p*i<=x) p *=i;
    if(p!=i&&p>ans) ans = p;
  }
  cout << ans << endl;
}