calculate first excitation energy of electron in h atom?

E = - E0/n^2
where E0 = 13.6 eV (1eV = 1.602 x 10^-19 joules) and n= 1
The first excitation energy of electron in hydrogen atom:
E= -13.6eV/1^2
= -13.6(1.602 x 10^-19 J)/1
= - 2.17872 x 10^-18