Theatre Square

//1A. Theatre Square
#include<stdio.h>
int main()
{
    long long int m,n,a,p,q,z;
    scanf("%lld %lld %lld",&m,&n,&a);

    p = m/a;
    if(p*a >= m)
        m = p * a;
    else
        m = (p+1) * a;

    q = n/a;
    if(q*a >= n)
        n = q * a;
    else
        n = (q+1) * a;


    z = ((m*n)/(a*a));
    printf("%lld",z);
    return 0;
}