A. Theatre Square

#include <stdio.h>
int main() {
long long n, m, a;
scanf("%lld %lld %lld", &n, &m, &a);
long long flength = (n + a - 1) / a;
long long fwidth = (m + a - 1) / a;
long long total_f = flength * fwidth;
printf("%lld\n", total_f);
return 0;
}