http://codeforces.com/contest/1
1 #include<bits/stdc++.h> 2 using namespace std; 3 const long long MOD=1e9+7; 4 5 int main(){ 6 long long n,m,a; 7 cin>>n>>m>>a; 8 long long aa=n/a; 9 if(n%a) aa++; 10 long long bb=m/a; 11 if(m%a) bb++; 12 cout<<aa*bb<<endl; 13 }