select count(1)
from
(select home_name,away_name,count(1) cnt
from MATCH
group by home_name,away_name
) a
,(select home_name,away_name,count(1) cnt
from MATCH
group by home_name,away_name
) b
where a.home_name=b.away_name
and a.away_name=b.home_name
and a.cnt<>b.cnt
;