If the following was implemented in a relational database, how many total foreign keys would the database have?

$\backslash$table$[[$Table Name,Primary Key,Foreign Key$],[$Employee$,$Employee#$,],[$Customer$,$Customer#$,],[$Sales$,$Sales#$,$Employee#$,$Customer#$],[$Inventory$,$Item#$,],[$Sales Inventory,Sales#$,$Item#$,]]$

$4$

$2$

$1$

$3$