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, m = 1, t;
  cin >> x;
  for(int i = 2; i < 33; i++) {
    t = i * i;
    if(t > x)
      continue;
    while(t <= x)
      t *= i;
    m = max(m, t / i);
  }
  cout << m << endl;
}