You are now a sqlite data analyst, and you are given a database schema as follows:

    【Schema】
    【DB_ID】 retail_world
【Schema】
# Table: Orders
[
(OrderID:INTEGER, Primary Key, Examples: [10248, 10249, 10250]),
(CustomerID:INTEGER, Examples: [90, 81, 34]),
(EmployeeID:INTEGER, Examples: [5, 6, 4]),
(OrderDate:DATETIME, Examples: [1996-07-04 00:00:00]),
(ShipperID:INTEGER, Examples: [3, 1, 2])
]
# Table: Suppliers
[
(SupplierID:INTEGER, Primary Key, Examples: [1, 2, 3]),
(SupplierName:TEXT, Examples: [Exotic Liquid]),
(ContactName:TEXT, Examples: [Charlotte Cooper, Shelley Burke, Regina Murphy]),
(Address:TEXT, Examples: [49 Gilbert St., P.O. Box 78934, 707 Oxford Rd.]),
(City:TEXT, Examples: [Londona, New Orleans, Ann Arbor]),
(PostalCode:TEXT, Examples: [EC1 4SD, 70117, 48104]),
(Country:TEXT, Examples: [UK, USA, Japan]),
(Phone:TEXT, Examples: [(171) 555-2222, (100) 555-4822, (313) 555-5735])
]
# Table: Customers
[
(CustomerID:INTEGER, Primary Key, Examples: [1, 2, 3]),
(CustomerName:TEXT, Examples: [Alfreds Futterkiste]),
(ContactName:TEXT, Examples: [Maria Anders, Ana Trujillo, Antonio Moreno]),
(Address:TEXT, Examples: [Obere Str. 57]),
(City:TEXT, Examples: [Berlin, México D.F., London]),
(PostalCode:TEXT, Examples: [12209, 5021, 5023]),
(Country:TEXT, Examples: [Germany, Mexico, UK])
]
# Table: OrderDetails
[
(OrderDetailID:INTEGER, Primary Key, Examples: [1, 2, 3]),
(OrderID:INTEGER, Examples: [10248, 10249, 10250]),
(ProductID:INTEGER, Examples: [11, 42, 72]),
(Quantity:INTEGER, Examples: [12, 10, 5])
]
# Table: Employees
[
(EmployeeID:INTEGER, Primary Key, Examples: [1, 2, 3]),
(LastName:TEXT, Examples: [Davolio, Fuller, Leverling]),
(FirstName:TEXT, Examples: [Nancy, Andrew, Janet]),
(BirthDate:DATE, Examples: [1968-12-08]),
(Photo:TEXT, Examples: [EmpID1.pic, EmpID2.pic, EmpID3.pic]),
(Notes:TEXT)
]
# Table: Shippers
[
(ShipperID:INTEGER, Primary Key, Examples: [1, 2, 3]),
(ShipperName:TEXT, Examples: [Speedy Express, United Package, Federal Shipping]),
(Phone:TEXT, Examples: [(503) 555-9831, (503) 555-3199, (503) 555-9931])
]
# Table: Products
[
(ProductID:INTEGER, Primary Key, Examples: [1, 2, 3]),
(ProductName:TEXT, Examples: [Chais, Chang, Aniseed Syrup]),
(SupplierID:INTEGER, Examples: [1, 2, 3]),
(CategoryID:INTEGER, Examples: [1, 2, 7]),
(Unit:TEXT, Examples: [10 boxes x 20 bags, 24 - 12 oz bottles, 12 - 550 ml bottles]),
(Price:REAL, Examples: [18.0, 19.0, 10.0])
]
# Table: Categories
[
(CategoryID:INTEGER, Primary Key, Examples: [1, 2, 3]),
(CategoryName:TEXT, Examples: [Beverages, Condiments, Confections]),
(Description:TEXT)
]
【Foreign keys】
Orders.EmployeeID=Employees.EmployeeID
Orders.CustomerID=Customers.CustomerID
Orders.ShipperID=Shippers.ShipperID
OrderDetails.OrderID=Orders.OrderID
OrderDetails.ProductID=Products.ProductID
Products.CategoryID=Categories.CategoryID
Products.SupplierID=Suppliers.SupplierID

    【Question】
    How many employees have Andrew Fuller as their direct supervisor? direct supervisor refers to ReportsTo where the person being reported to is usually the direct supervisor of the reporter;

    【Evidence】
    direct supervisor refers to ReportsTo where the person being reported to is usually the direct supervisor of the reporter;

    Please read and understand the database schema carefully, and generate an executable SQL based on the user's question and evidence. 

SQL: SELECT COUNT(EmployeeID) FROM Employees WHERE ReportsTo = ( SELECT EmployeeID FROM Employees WHERE LastName = 'Fuller' AND FirstName = 'Andrew' )