CodeForces 1A Theatre Square

import java.util.*;
import java.math.*;

public class Main {
    public static void main(String[] args) {
        BigInteger zero=new BigInteger("0"); 
        BigInteger one=new BigInteger("1"); 
        Scanner sc=new Scanner(System.in);
        while(sc.hasNext()){
            BigInteger n=sc.nextBigInteger();
            BigInteger m=sc.nextBigInteger();
            BigInteger a=sc.nextBigInteger();

            BigInteger x,y;
      
            if(n.remainder(a).equals(zero))
                x=n.divide(a);
            else
                x=n.divide(a).add(one);
        
            if(m.remainder(a).equals(zero))
                y=m.divide(a);
            else
                y=m.divide(a).add(one);

            System.out.println(x.multiply(y));
        }
    }
}