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 tmp=i;
        while(tmp*i<=x)tmp*=i;
        ans=max(ans,tmp);
    }
    cout << ans << endl;
}