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 Julia (0.5.0) (judge verdict: Wrong Answer)

function main()
  
  X = parse(Int, readline())
  
  ans = 0

  for i in 1:X, j in 2:X
    
    if X < i^j || i^j <= 0
      continue
    else
      ans = i^j
    end
    
  end
  
  println(ans)
  
end

main()