Problem:
Score : 200 points

Problem Statement

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.

Sample Input 1

10

Sample Output 1

9

There are four perfect powers that are at most 10: 1, 4, 8 and 9.
We should print the largest among them, 9.

Sample Input 2

1

Sample Output 2

1

Sample Input 3

999

Sample Output 3

961

Solution in C# (Mono 4.6.2.0) (judge verdict: Accepted)

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;


class Program
{


    static void Main(string[] args)
    {
        Solve();
    }

    static void Solve()
    {
        Scan sc = new Scan();
        write wr = new write();

        var x = sc.intarr[0];

        int ma = 1;
        for(int i = 1; i <= 35; ++i)
        {
            for(int j = 2; j <= 10; ++j)
            {
                
                if ((int)Math.Pow(i, j) <= x&& (int)Math.Pow(i, j)>=1)
                {

                    int l = (int)Math.Pow(i, j);
                    //wr.wri(l);
                    ma = Math.Max(ma, l);
                }
            }
        }

        wr.wri(ma);

    }


}
    class Scan
    {
        public string str => Console.ReadLine();

        public string[] strarr => str.Split(' ');

        public long[] longarr => strarr.Select(long.Parse).ToArray();
        public int[] intarr => strarr.Select(int.Parse).ToArray();
        public char[] chararr => str.ToArray();


}



class write
{
    public void wri<Type>(Type x)
    {
        Console.WriteLine(x);
    }
}