When I try, for example, this query:

SELECT count(id) FROM Contacts where (First_Name in ('Name1', 'Name2'))

I get error:

{"code":"SYNTAX_ERROR","details":{"clause":"group by"},"message":"missing clause","status":"error"}

After I add GROUP BY clause:

SELECT count(id) FROM Contacts where (First_Name in ('Name1', 'Name2')) group by id

I get error:

{"code":"INVALID_QUERY","details":{"clause":"group by","column_name":"count(id)"},"message":"select column should be given in group by clause","status":"error"}

How to construct correct query in order to return total count info?