— function: ideal-nucleic-acid RNA_or_DNA form single_stranged_flag sequence

Where:

• RNA_or_DNA is a string
• form is a string
• single_stranged_flag is an integer number
• sequence is a string

create a molecule of idea nucleotides

use the given sequence (single letter code)

RNA_or_DNA is either "RNA" or "DNA"

form is either "A" or "B"

Returns: the new molecule number or -1 if a problem