1a.rs

use std::io;
use std::str::FromStr;
use std::num::Float;

// http://codeforces.com/contest/1/problem/A
fn main() {
    let l = io::stdin().read_line().unwrap();
    // We need the .trim() because of the newline. Annoying
    // Can't do it on one line because of lifetime error. Also annoying.
    let l = l.trim();
    let v: Vec<&str> = l.split(' ').collect();
    let n: f32 = FromStr::from_str(v[0]).unwrap();
    let m: f32 = FromStr::from_str(v[1]).unwrap();
    let a: f32 = FromStr::from_str(v[2]).unwrap();

    let num_rows = (n / a).ceil();
    let num_cols = (m / a).ceil();
    println!("{}", num_rows * num_cols);
}