function locked()
  shell.run ("Screen")
  print ("The Computer has been locked because of safety reasons.")
  print ("Someone tried to brute force the computer")
  print ("Call a technician and let him enter the master-password")
  write ("Masterpassword:")
  local enter = read("*")
  if enter == "einfachespasswort123" then
    shell.run("startup")
  else
    shell.run("Screen")
    write ("Nice try but try harder. The computer is now locked for 10 minutes")
    sleep (600)
    locked()
  end
end
function welcome()
  -- Welcome Screen
  shell.run ("Screen")
  term.setCursorPos (22,7)
  write ("---------")
  term.setCursorPos (22,8)
  print ("|Welcome|")
  term.setCursorPos (22,9)
  write ("---------")
  sleep (5)
end

welcome()
local i = 0
while i < 3 do
  shell.run("Screen")
  term.setCursorPos (1,4)
  write ("Username:")
  term.setCursorPos (1,5)
  write ("Password:")
  term.setCursorPos (10,4)
  local username = read()
  term.setCursorPos (10,5)
  local password = read("*")
  if username == "test" and password == "test" then
    globalusername = ampel14235
    shell.run("email")
  else
    i = i + 1
    local left = 3 - i
    shell.run ("Screen")
    term.setCursorPos (1,4)
    write ("Wrong username and/or password. "..left.." try(s) left")
    sleep (5)
  end
end
locked()