uva 11044 Searching for Nessy

The Loch Ness Monsteris a mysterious and unidentified animal said to inhabit Loch Ness,  a large deep freshwater loch near the city of Inverness in northern Scotland. Nessie is usually categorized as a type of lake monster. http://en.wikipedia.org/wiki/Loch_Ness_Monster     In July 2003, the BBC reported an extensive investigation of Loch Ness by a BBC team, using 600 separate sonar beams, found no trace of any ¨sea monster¨ (i.e., any large animal, known or unknown) in the loch. The BBC team concluded that Nessie does not exist. Now we want to repeat the experiment.     Given a grid of n rows and m columns representing the loch, 6n, m10000, find the minimum number s of sonar beams you must put in the square such that we can control every position in the grid, with the following conditions:   For example,  

  where X represents a sonar, and the shaded cells are controlled by their sonar beams; the last figure gives us a solution.   The first line of the input contains an integer, t, indicating the number of test cases. For each test case, there is a line with two numbers separated by blanks, 6n, m10000, that is, the size of the grid (n rows and m columns).   For each test case, the output should consist of one line showing the minimum number of sonars that verifies the conditions above.           貌似题目很长很难，其实很简单，稍微思考一下就可以了，没必要过多解释。这种题目要重视，千万不要被题目的长度吓住了。这种题目是纸老虎。

拙劣的代码

#include <iostream>
#include <cstdlib>
#include <cstdio>

using namespace std;

int main(void)
{
    int n, m, t;

    cin >> t;
    while (t--)
    {
        cin >> n >> m;
        n -= 2; m-= 2;
        n = n / 3 + (n % 3 != 0);
        m = m / 3 + (m % 3 != 0);
        cout << n * m << endl;
    }

    return 0;
}