Comparison of the abundance of [(C+N)/Fe]. (i) For the sample of EMP stars studied in the framework of the Large Program First Stars: filled blue squares for unmixed RGB stars, filled red diamonds for mixed RGB’s, and filled black circles for the turnoff stars (no EMP turnoff stars appear in this figure, because it was not possible to measure the nitrogen abundance in these stars Bonifacio et al. 2009); (ii) for CEMP-no (open green crosses); (iii) for CEMP-s (open green circles), and (iv) for the three low-[Sr/Ba] giants here studied (open pink star symbols). These three low-[Sr/Ba] stars are located in the region generally occupied by the carbon-rich stars.