removed sslc1.txt from circulate since it is not required
s = "1, 3-7, 12, 15, 18-21"answer = []single = "answer.append( %s )"many = "answer.extend(range(%s))"COMMA = ','MINUS = '-'for p in s.split(COMMA): if MINUS not in p: eval( single % (p) ) else: p = p.replace( MINUS, COMMA) + '+ 1 ' eval( many % (p) )print answer