What is the shortest wavelength present in the Paschen series of spectral lines?

Longest wavelengths in Balmer series of He^(+1) is

If the wavelength of spectral lines emitted by hydrogen atom is generally expressed as [1/lambda = R(1/m^2) - (1/n^2)] Where R: Rydberg Constant and .n. and .m. are integers. From this, : Write down the expression for Balmer series of spectral lines.

The longest wavelength of He^(+) when its electron return to third Bohr orbit is ‘m' then shortest wavelength of Be^(3+) in the corresponding transition series in terms of 'm' is

Calculate the wavelength of the second line in Balmer series.