In East Slavic languages, which are basically of singular–plural system, the singular suffix -ин- ('-in-', Russian', -yn-', Ukrainian), resp. '-ін- '('-in-', Belarusian) performs the singulative function for collective nouns. Russian: "gorokh" (peas in mass) vs. "goroshina" (a single pea). Ukrainian: /"pisok" (sand) vs. /"pischyna" (grain of sand). Belarusian: (potatoes in mass, e.g. as a crop or as a species) vs. (one potato tuber). Notice the affix '-a' in all these examples, which indicates the feminine form. Notice also that plural forms may be derived from these singulatives in a regular way: "goroshina"->"goroshiny" (several peas), etc.