2011 - Episode I Problem B

#include <fstream>

using namespace std;

int main()
{
    int ans(0), N(0), M(0);

    ifstream ifs("forcycle.in");
    ifs >> N >> M;
    ifs.close();

    for (int i = 1; i <= N; i++)
        ans += (i % M);

    ofstream ofs("forcycle.out");
    ofs << ans;
    ofs.close();
}