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: Accepted)

require "bigdecimal"
require "bigdecimal/util"

def gi() gets.to_i end
def gs() gets.chomp end
def gim() gets.split.map(&:to_i) end
def gsm() gets.split.map(&:chomp) end
def YesNo1(bool, yes="Yes", no="No") puts (bool ? yes : no) end
def YESNO2(bool, yes="YES", no="NO") puts (bool ? yes : no) end

#####
x = gi
res = (x/500.0).floor * 1000
x = x % 500
res += (x/5.0).floor * 5
puts res