通过率只有60

#include "bits/stdc++.h"
using namespace std;
int main(){
    int m,n,a;
    int sum1,sum2;
    scanf("%d""%d""%d",&m,&n,&a);
    if(m%a==0)
        sum1=m/a;
    
    else 
        sum1=m/a+1;
    
    if(n%a==0)
        sum2=n/2;
    
    else sum2=n/a+1;
    
    printf("%d",sum1*sum2);
    return 0;
}