fn main() {
    let mut nhw = String::new();
    std::io::stdin().read_line(&mut nhw).ok();
    let nhw: Vec<usize> = nhw.trim().split_whitespace().map(|s| s.parse().unwrap()).collect();
    let n = nhw[0];
    let h = nhw[1];
    let w = nhw[2];

    println!("{}", n/2*(n/2+n%2)*(h+w-2));
}