SELECT COUNT(DISTINCT name) FROM photos
How many distinct names are associated with all the photos?
CREATE TABLE street_markets (
    market_id number,
    market_details text
)

CREATE TABLE ref_hotel_star_ratings (
    star_rating_code text,
    star_rating_description text
)

CREATE TABLE features (
    feature_id number,
    feature_details text
)

CREATE TABLE staff (
    staff_id number,
    tourist_attraction_id number,
    name text,
    other_details text
)

CREATE TABLE photos (
    photo_id number,
    tourist_attraction_id number,
    name text,
    description text,
    filename text,
    other_details text
)

CREATE TABLE shops (
    shop_id number,
    shop_details text
)

CREATE TABLE ref_attraction_types (
    attraction_type_code text,
    attraction_type_description text
)

CREATE TABLE royal_family (
    royal_family_id number,
    royal_family_details text
)

CREATE TABLE hotels (
    hotel_id number,
    star_rating_code text,
    pets_allowed_yn text,
    price_range number,
    other_hotel_details text
)

CREATE TABLE museums (
    museum_id number,
    museum_details text
)

CREATE TABLE tourist_attractions (
    tourist_attraction_id number,
    attraction_type_code text,
    location_id number,
    how_to_get_there text,
    name text,
    description text,
    opening_hours text,
    other_details text
)

CREATE TABLE locations (
    location_id number,
    location_name text,
    address text,
    other_details text
)

CREATE TABLE theme_parks (
    theme_park_id number,
    theme_park_details text
)

CREATE TABLE visitors (
    tourist_id number,
    tourist_details text
)

CREATE TABLE tourist_attraction_features (
    tourist_attraction_id number,
    feature_id number
)

CREATE TABLE visits (
    visit_id number,
    tourist_attraction_id number,
    tourist_id number,
    visit_date time,
    visit_details text
)