Theatre Square

#include<stdio.h>
int main()
{
    long long int m,n,a,x,y;
    scanf("%lld %lld %lld",&m,&n,&a);
    x = m/a;
    y = n/a;
    if(x%a!=0)
        x++;
    if(y%a!=0)
        y++;
    printf("%lld\n",x*y);
    return 0;
}