For the male users no older than 18, how many times have they given the highest rating?
Male users refers to u_gender = 'M'
SELECT COUNT(T1.movieid) FROM u2base AS T1 INNER JOIN users AS T2 ON T1.userid = T2.userid WHERE T1.rating = 5 AND T2.age < 18 AND T2.u_gender = 'M'
database name:db_id movielens
users table users Cols: user id dtype integer, age dtype text, user gender dtype text, occupation dtype text, 
directors table directors Cols: director id dtype integer, director quality dtype integer, average revenue dtype integer, 
actors table actors Cols: actor id dtype integer, actor gender dtype text, actor quality dtype integer, 
movies table movies Cols: movie id dtype integer, year dtype integer, is English dtype text, country dtype text, runningtime dtype integer, 
movies2actors table movies2actors Cols: movie id dtype integer, actor id dtype integer, cast number dtype integer, 
movies2directors table movies2directors Cols: movie id dtype integer, director id dtype integer, genre dtype text, 
u2base table u2base Cols: user id dtype integer, movie id dtype integer, rating dtype text, 
