function main()
    local marks::Int32
    local out::Int32
    marks = 81
    if 91 ≤ marks ≤ 100
        out = 0
        println("Excellent!")
    elseif 81 ≤ marks ≤ 90
        out = 1
        println("Very good!")
    elseif 71 ≤ marks ≤ 80
        out = 2
        println("Well done!")
    elseif 61 ≤ marks ≤ 70
        out = 3
        println("Not bad!")
    elseif 41 ≤ marks ≤ 60
        out = 4
        println("You passed!")
    elseif marks ≤ 40
        out = 5
        println("Better try again!")
    else
        out = 6
        println("Invalid marks")
    end
    println("Your marks are ", " ", marks)
    if out ≠ 1
        println(Base.stderr, "ERROR STOP")
        exit(1)
    end
    if 91 ≤ marks ≤ 100
        println("Excellent!")
    elseif 81 ≤ marks ≤ 90
        println("Very good!")
    elseif 71 ≤ marks ≤ 80
        println("Well done!")
    elseif 61 ≤ marks ≤ 70
        println("Not bad!")
    elseif 41 ≤ marks ≤ 60
        println("You passed!")
    elseif marks ≤ 40
        println("Better try again!")
    else
        println("Invalid marks")
    end
    println("Your marks are ", " ", marks)
    if 91 ≤ marks ≤ 100
        println("Excellent!")
    elseif 81 ≤ marks ≤ 90
        println("Very good!")
    elseif 71 ≤ marks ≤ 80
        println("Well done!")
    elseif 61 ≤ marks ≤ 70
        println("Not bad!")
    elseif 41 ≤ marks ≤ 60
        println("You passed!")
    elseif marks ≤ 40
        println("Better try again!")
    else
        println("Invalid marks")
    end
    println("Your marks are ", " ", marks)
end

main()
