human
Considering the provided database schema and associated query, produce SQL code to retrieve the answer to the query. 
###Database Schema: Masculine a-stems, Masculine u-stems, Feminine ō-stems, Neuter a-stems, Masculine an-stems, Feminine ōn-stems
###Question: What is the an-stem for the word which has an ö-stems of siangar and an u-stem ending of syni?
gpt
SELECT Masculine an-stems FROM table WHERE Feminine ō-stems = siangar AND Masculine u-stems = syni