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,ans=1;cin>>x;
    for(int i=2;pow(i,2)<=x;i++){
        int k=2,v=i;
        while(v<=x){
            v*=i;
            if(v>x) ans=max(ans,v/i);
        }
    }
    cout<<ans<<endl;
}