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 X;
int R = 1;

int main() {
  cin >> X;
  for(int b = 2; b * b <= X; ++b) {
    int c = b * b;
    while(b * c <= X) c *= b;
    R = max(R, c);
  }
  cout << R << endl;
  return 0;
}
