static void Main(string[] args)
{
do
{
int n = SoNguyen.NhapSoNguyenDuong("Nhap n = ");
float kq = TinhToan.tinh(n);
Console.Write("S(" + n + ") = " + kq);
} while (SoNguyen.NhapSoNguyen("\nTiep tuc (1.Tiep, 0.Khong)? ") != 0);
}