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 Rust (1.15.1) (judge verdict: Accepted)

pub struct Scanner{
    line : Vec<String> ,
    idx : usize
}

impl  Scanner{
   #[allow(dead_code)]
   fn new() -> Scanner{
       return Scanner{ line: vec![], idx : 0}
   }
   #[allow(dead_code)]
   fn next<T: std::str::FromStr> (&mut self) -> T{
       if self.idx == self.line.len() {
           let mut buffer = String::new();
           std::io::stdin().read_line(&mut buffer).ok();

           let a : Vec<&str>  = buffer.trim().split(' ').collect();
           self.line = a.iter().map(|&s| String::from(s)).collect();
           self.idx = 0;
       }
       let ret : T = self.line[self.idx].parse::<T>().ok().expect("Parse error.");
       self.idx += 1;
       ret
   }
   #[allow(dead_code)]
   fn read_vec<T: std::str::FromStr>  (&mut self, n: usize) -> Vec<T>{
       let mut v : Vec<T>= Vec::with_capacity(n);
       for _i in 0..n {
           v.push(self.next());
       }
       v
   }
}


fn main() {
    let mut scan = Scanner::new();
    let x:i32  = scan.next();
    
    println!("{}", x/500*1000 + x%500/5*5);
}