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 i = 2; i*i <= n; i++) {
    int tmp = i;
    while (tmp <= n) tmp*=i;
    tmp /= i;
    ans = max(ans, tmp);
  }
  cout<<ans<<endl;
}
