Jam from pears and apples for the winter in slices

Wash the fruit, cut into slices, cutting out the core and seeds. Put the fruit in a saucepan like this: apples + sugar on top, pears + sugar on top.
Put the pan on the stove on low heat and heat to 80C. Turn off the heat, close the lid of the pan and leave for 10 hours.
Turn on the stove again, bring the jam to a boil over low heat. The sugar must be dissolved. Turn off the stove, cover the jam and leave for 10 hours. And do it 2 more times.
Put the jam in sterilized jars and roll up. Turn over and wrap in a towel until completely cooled.