CF_1A Theatre Square

#include<iostream>using namespace std;int main(){    long long a,m,n,x,y,sum;    while(cin>>n>>m>>a)    {        x=0;y=0;sum=0;    if((m>=a))    {        x=m/a+1;        if(m%a==0) x--;    }    else if(m<a) x=1;    if(n>=a)    {        y=n/a+1;        if(n%a==0) y--;    }    else if(n<a) y=1;    sum=x*y;    cout<<sum<<endl;    }

}