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;
  cin >> x;
  int ans = 1;
  for(int i=2;i*i<=x;i++){
  	int cur = i;
    while(cur*i<=x){
    	cur*=i;
      	ans = max(ans,cur);
    }
  }
  cout << ans << endl;
 
  
}