Problem:
Score : 200 points

Problem Statement

Takahashi loves gold coins. He gains 1000 happiness points for each 500-yen coin he has and gains 5 happiness points for each 5-yen coin he has. (Yen is the currency of Japan.)

Takahashi has X yen. If he exchanges his money so that he will gain the most happiness points, how many happiness points will he earn?

(We assume that there are six kinds of coins available: 500-yen, 100-yen, 50-yen, 10-yen, 5-yen, and 1-yen coins.)

Constraints

0 \leq X \leq 10^9

X is an integer.

Input

Input is given from Standard Input in the following format:

X

Output

Print the maximum number of happiness points that can be earned.

Sample Input 1

1024

Sample Output 1

2020

By exchanging his money so that he gets two 500-yen coins and four 5-yen coins, he gains 2020 happiness points, which is the maximum number of happiness points that can be earned.

Sample Input 2

0

Sample Output 2

0

He is penniless - or yenless.

Sample Input 3

1000000000

Sample Output 3

2000000000

He is a billionaire - in yen.

Solution in Ruby (2.3.3) (judge verdict: Wrong Answer)

class InputLine
  def self.to_s
    gets.chomp
  end

  def self.to_i
    InputLine.to_s.to_i
  end
  
  def self.to_f
    InputLine.to_s.to_f
  end

  def self.to_sa
    InputLine.to_s.split(' ')
  end

  def self.to_ia
    InputLine.to_sa.map(&:to_i)
  end
  
  def self.to_fa
    InputLine.to_sa.map(&:to_f)
  end
end

def main(argv)
  x = InputLine.to_i

  p = x / 500

  x = x % 500

  q = p % 5

  puts (p * 1000 + q * 5).to_s
end

if self.to_s == 'main' then
  main(ARGV)
end