Example of a RSG spectrum observed with WINERED: namely that of Betelgeuse in the Y band (echelle orders 57-52). Black thick lines show the reduced spectrum of Betelgeuse, after telluric lines were removed. Gray thin lines show the spectrum of the corresponding telluric standard A0V star, HIP 27830, after the stellar lines were removed. Red thick vertical dashed lines near the top edge of each panel indicate the wavelengths of the lines from the VALD3 and/or MB99 line list used for measuring [X/H]. Light-red thin vertical dashed lines indicate the wavelengths of the candidate lines preselected in Sects. 3.3 and 3.6 from VALD3 and/or MB99 but eventually rejected in Sects. 3.5.2 and 3.6 for both line lists.