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<=1000; ++i)
    {
        int st = i*i;
        for(;st<=X;st*=i)
        ans = max(ans, st);
    }
    cout<<ans<<endl;
}