function start()
    api.mtext(1,1,"-------------------------------------------------")
    api.mtext(1,3,"-------------------------------------------------")
    api.mtext(15,2,"zxvnm4's master control")
    gh = {1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16}
    for i,g in ipairs(gh) do
        api.mtext(1,3+i,"|                                               |")
    end
    page1 = {"user","idk"}
    page2 = {"remove","add","exit"}
    page3 = {"on","off","exit"}
    sel = 1
    redo = true
    page = 1

    while redo == true do
        l = 0
        if page == 1 then
            op = page1
        end
        if page == 2 then
            op = page2
        end
        if page == 3 then
            op = page3
        end
        if page == 4 or page == 5 then
            op == {}
        end

        for i,v in pairs(op) do
            term.setCursorPos(22,7+i)
            if i == sel then
                term.write("<" .. op[i] .. ">")
            else
                term.write(" " .. op[i] .. " ")
            end
            l = l + 1
        end
    ev, k = os.pullEvent()

    if ev == "key" then
    if k == 200 then sel = sel-1 end
    if k == 208 then sel = sel+1 end
    if sel<1 then sel = l end
    if sel>l then sel = 1 end
    if k == 57 or k == 28 then
        if page == 4 then
            api.mtext(22,6,"put username and permission")
            api.mtext(22,7,"username: ")
            user = read()
            api.mtext(22,8,"permission: ")
            perm = read()
            api.adduser(user,perm)
        end
        if page == 5 then
            api.mtext(22,6,"put username of remove")
            api.mtext(22,7,"username: ")
            user = read()
            api.removeuser(user)
        end
        if page == 2 then
            if sel == 1 then
                page = 5
            end
            if sel == 2 then
                page = 4
            end
            if sel == 3 then
                page = 1
            end
        end
        if page == 3 then
            if sel == 1 then
                api.
            end
            if sel == 2 then

            end
            if sel == 3 then
                page =1
            end
        end
        if page == 1 then
            if sel == 1 then
                page = 2
            end
            if sel == 2 then
                    page = 3
                end
            end
        end

    end
end
end


function startu()
sleep(0.1)
api.clearline(9)
api.mtext(10,6,"___________________________")
api.mtext(10,7,"|     master computer     |")
api.mtext(10,8,"|                         |")
api.mtext(10,10,"|  password:              |")
api.mtext(10,11,"|_________________________|")
api.mtext(10,9,"|  username: ")
user = read()
api.clearline(9)
api.mtext(10,9,"|  username: "..user)
api.mtext(36,9,"|")
api.mtext(10,10,"|  password: ")
pass = read()
if pass == api.getpass(user) then
term.clear()
sleep(0.5)
start()
else
api.mtext(2,2,"your password/username is incorrect")
sleep(2)
api.clearline(8)
startu()
end
end
startu()