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

  if X == 1
    ans = 1
  else
  
  for i in 1:X
    
    for j in 2:X
    
    	if X < i^j
      	break
    	else
      	ans = i^j
    	end
      
    end
    
  end
    
  end
  
  println(ans)
  
end

main()