Tính tổng \(S = \dfrac{1}{{2018}}{\left( {C_{2018}^1} \right)^2} + \dfrac{2}{{2017}}{\left( {C_{2018}^2} \right)^2} + ... + \dfrac{{2017}}{2}{\left( {C_{2018}^{2017}} \right)^2} + \dfrac{{2018}}{1}{\left( {C_{2018}^{2018}} \right)^2}\)