CREATE TABLE "roster" (
  "name" text,
  "num" real,
  "position" text,
  "height" text,
  "weight" real,
  "year" text,
  "former_school" text,
  "hometown" text
);

Question: Name the most number for notre dame prep
SQL: SELECT MAX("num") FROM "roster" WHERE "former_school"='Notre Dame Prep';