use std::io::*;

fn main() {
    let mut s: String = String::new();
    std::io::stdin().read_to_string(&mut s).ok();
    let mut itr = s.trim().split_whitespace();
    let a: i64 = itr.next().unwrap().parse().unwrap();
    let b: i64 = itr.next().unwrap().parse().unwrap();
    let mut c = 0;
    while b * 1000 * (c + 1) <= a {
        c += 1;
    }
    println!("{}", 1000 * c);
}