Lua Login

adminu = "Admin"
adminp = "test"
user1u = "User1"
user1p = "test"
user2u = "User2"
user2p = "test"
user3u = "User3"
user3p = "test"
na = "Not Applicable"
write("Username: ")
a = io.read()
write("Password: ")
b = io.read()
if a == adminu and b == adminu then
    write "Login for"
    write(adminu)
    print "was successful"
    os.shell("GUI")
else if a == user1u and b == user1p then
    write "Login for"
    write(user1u)
    print "was successful"
    os.shell("GUI")
    write "Login for"
    write(user2u)
    print "was successful"
    os.shell("GUI")
else if a == user3u and b == user3p then
    write "Login for"
    write(user3u)
    print "was successful"
    os.shell("GUI")
else
    write "Login unseccessful"
end