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, ans = 1;
  cin >> x;
  int n = sqrt(x);
  for (int i = n; i > 1; i--) {
    int j = i * i;
    while (j <= x) {
      ans = max(ans, j);
      j *= i;
    }
  }
  cout << ans;
}