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;
  cin >> a;
  b = 1;
  for (int i = 2; i < a; i++) {
    for (int j = 2; a >= pow(i, j); j++) {
      int c = pow(i, j);
      if (c > b) b = c;
    }
  }
  cout << b << endl;
}