procedure main(A)
    maxCount := count := 0

    every !&input ?  case tab(upto('@')) of {
        "License OUT ": {
             maxTime := (maxCount <:= (count +:= 1), [])
             put(maxTime, (maxCount = count, ="@ ", tab(find(" for "))))
             }
        "License IN  ": count -:= (count > 0, 1)     # Error check
        }

    write("There were ",maxCount," licenses out at:")
    every write("\t",!maxTime)
end