SELECT accreditation_level FROM phone GROUP BY accreditation_level HAVING COUNT(*) > 3
Find the accreditation level that more than 3 phones use.
CREATE TABLE screen_mode (
    graphics_mode number,
    char_cells text,
    pixels text,
    hardware_colours number,
    used_kb number,
    map text,
    type text
)

CREATE TABLE chip_model (
    model_name text,
    launch_year number,
    ram_mib number,
    rom_mib number,
    slots text,
    wifi text,
    bluetooth text
)

CREATE TABLE phone (
    company_name text,
    hardware_model_name text,
    accreditation_type text,
    accreditation_level text,
    date text,
    chip_model text,
    screen_mode text
)