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;
long long ans =1;
for(int i=2;i<=x+10;i++){
  long long a =i*i;
  while(1){
    if(a>x){
      break;
    }    
    ans = max(ans,a);
    a*=i;

  }
}
cout << ans << endl;
}

