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 Kotlin (1.0.0) (judge verdict: Wrong Answer)

fun main(array: Array<String>) {
    val x = readLine()!!.toInt()
    var max = 1
    for(i in 1..x) {
        for(j in 1..i) {
            if(j * j == i) {
                if(i > max) max = i
            }
        }
    }
    print(max)
}