Below is the list of tables from the database along with their columns and datatype. Need to generate an accurate SQL query for the question.
Only use the columns present in the respective table. Only use the columns which are required to generate the SQL query. Only use table joins if required and not otherwise.

### Tables ###
TABLE: CREATE TABLE table_77491 ( "Masculine a-stems" text, "Masculine u-stems" text, "Feminine \u014d-stems" text, "Neuter a-stems" text, "Masculine an-stems" text, "Feminine \u014dn-stems" text )

### Question ###
What is the an-stem for the word which has an -stems of siangar and an u-stem ending of syni?

### Accurate SQL ###

SELECT "Masculine an-stems" FROM table_77491 WHERE "Feminine \u014d-stems" = 'siangar' AND "Masculine u-stems" = 'syni'