use std::io;
use std::str::FromStr;

fn main() {
    let stdin = io::stdin();
    let mut buf = String::new();
    stdin.read_line(&mut buf).ok();

    let mut it = buf.split_whitespace().map(|n| u64::from_str(n).unwrap());
    let a = it.next().unwrap();

    let mut buf = String::new();
    stdin.read_line(&mut buf).ok();

    let mut it = buf.split_whitespace().map(|n| u64::from_str(n).unwrap());
    let b = it.next().unwrap();

    let d = a / b;

    if d < 1000 {
        println!("{}", 0);
        return;
    }
    println!("{}", d - d % 1000);
}