SELECT MIN("Parishes") FROM table_43915 WHERE "Pastoral Region" = 'merrimack' AND "Cemeteries" < '4'
How many Parishes in Merrimack which has 4 Cemeteries?
CREATE TABLE table_43915 (
    "Pastoral Region" text,
    "Episcopal vicar" text,
    "Parishes" real,
    "High schools" real,
    "Elementary schools" text,
    "Cemeteries" real
)