A - Theatre Square比赛1

1.题目：

A - Theatre Square
Time Limit:2000MS     Memory Limit:65536KB     64bit IO Format:%I64d & %I64u
Submit
 
Status
 
Practice
 
CodeForces 1A
Description
Theatre Square in the capital city of Berland has a rectangular shape with the size n × m meters. On the occasion of the city's anniversary, a decision was taken to pave the Square with square granite flagstones. Each flagstone is of the size a × a.

What is the least number of flagstones needed to pave the Square? It's allowed to cover the surface larger than the Theatre Square, but the Square has to be covered. It's not allowed to break the flagstones. The sides of flagstones should be parallel to the sides of the Square.

Input
The input contains three positive integer numbers in the first line: n,  m and a (1 ≤  n, m, a ≤ 109).

Output
Write the needed number of flagstones.

Sample Input
Input
6 6 4
Output
4

2.代码：

#include
int main()
{
    __int64 m,n,a;
    __int64 ans1,ans2;
    scanf("%I64d%I64d%I64d",&m,&n,&a);
    if(m%a>0)
    ans1=m/a+1;
    else
    ans1=m/a;
    if(n%a>0)
    ans2=n/a+1;
    else
    ans2=n/a;
    printf("%I64d\n",ans1*ans2);

}
/*
1000000000 1000000000 192
*/