local computer=require("computer")

local seconds=math.floor(computer.uptime())
local minutes,hours=0,0
if seconds>=60 then
minutes=math.floor(seconds/60)
seconds=seconds%60
end
if minutes>=60 then
hours=math.floor(minutes/60)
minutes=minutes%60
end
io.write(string.format("%02d:%02d:%02d\n",hours,minutes,seconds))