So basically, inside our skin cells we use UV radiation. So the energy that comes from UV radiation to basically transform colicalcipheral, or actually to form colicalcipherel. And then the colicalcipheral, which is basically vitamin D, travels into our liver. And inside the liver the colicalciphal is transformed into our calcitial. And then the calcitial that is formed in the liver travels into our kidneys. And inside the kidneys the calcitiol is transformed into our calcitriole.