fn main() {
    let mut s = String::new();
    std::io::stdin().read_line(&mut s).ok();
    let mut itr = s.trim().split_whitespace();
    let mut l: usize = itr.next().unwrap().parse().unwrap();
    let mut r: usize = itr.next().unwrap().parse().unwrap();
    let mut c: usize = itr.next().unwrap().parse().unwrap();

    let mut ans: usize = 1000;

    for i in l..=std::cmp::min(l + 999, r) {
        ans = std::cmp::min(ans, (1000 - i * c % 1000) % 1000)
    }

    println!("{}", ans);
}