Table state after a MERGE

target has (id, v): (1, 10), (2, 20), (3, 30). staging has (2, 25), (4, 40), (5, 50). After this MERGE, how many rows does target have and what is SUM(v)?

MERGE INTO target t
USING staging s ON t.id = s.id
WHEN MATCHED THEN UPDATE SET v = s.v
WHEN NOT MATCHED THEN INSERT (id, v) VALUES (s.id, s.v);