#[macro_export]
macro_rules! setup {
    { mut $input:ident: SplitWhitespace $(,)? } => {
        use std::io::Read;
        let mut buf = String::new();
        std::io::stdin().read_to_string(&mut buf).ok();
        let mut $input = buf.split_whitespace();
    };
}

#[macro_export]
macro_rules! parse_next {
    ($str_iter:expr) => {
        $str_iter.next().unwrap().parse().ok().unwrap()
    };
}

fn main() {
    setup! { mut input: SplitWhitespace };

    let n: usize = parse_next!(input);
    let m: usize = parse_next!(input);
    let p: f64 = parse_next!(input);

    let ans = (|| {
        let mut e = 0.0;
        match (n, m) {
            (1, 1) => {
                e += p;
            }
            (1, _) => {
                for j in 0..m {
                    if j == 0 || j == (m - 1) {
                        e += p * p;
                    } else {
                        e += p * (p * p);
                    }
                }
            }
            (_, 1) => {
                for i in 0..n {
                    if i == 0 || i == (n - 1) {
                        e += p * p;
                    } else {
                        e += p * (p * p);
                    }
                }
            }
            (_, _) => {
                for i in 0..n {
                    for j in 0..m {
                        if i == 0 || i == (n - 1) {
                            if j == 0 || j == (m - 1) {
                                e += p * (p * p);
                            } else {
                                e += p * (p * p * p);
                            }
                        } else {
                            if j == 0 || j == (m - 1) {
                                e += p * (p * p * p);
                            } else {
                                e += p * (p * p * p * p);
                            }
                        }
                    }
                }
            }
        }
        e
    })();

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