Complex sentence: In alphabetizing German words, ß is treated as double "s"; thus, "Ruß" comes before "Russe", which comes before "rußen", which comes before "Russland".
Split into simpler sentences: In alphabetizing German words, ß is treated as double "s". Thus, "Ruß" comes before "Russe", which comes before "rußen", which comes before "Russland".