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 (GCC 5.4.1) (judge verdict: Wrong Answer)

#include <stdio.h>
#include <string.h>
#include <stdbool.h>

int main()
{
    int n;
    scanf("%d¥n", &n);

    int cnt = 0;
    for(int i = 1; i<= n; ++i)
    {
        for(int j = 2; j <=n; ++j)
        {
            int m = 1;
            for(int k = 0; k < j; ++k)
            {
                m *= i;
            }
            if(m <= n && cnt < m)
            {
                cnt = m;
            }
        }
    }

    printf("%d\n", cnt);

    return 0;
}