x1 = E x2 = E_P_1 x3 = P x4 = M x5 = M1 x6 = E_M1 x7 = E_M x8 = T x9 = E_P_2 x10 = P2 x11 = P21 x12 = E_P21 x13 = E_P2 x14 = E_P1