I remember when we lived in a student dormitory, we often did something with each other. There was no money, we took food. I once borrowed 15 frozen peelings to eat with a neighbor. And when he bought pelletry for himself, cooked it, ate it, he didn't calculate something, and only fourteen pieces remained. I took off his debt and added two bulbs for the missing peel. The neighbor was not against. A couple of months later, the frozen peelmen was exchanged for two bulbs throughout the community and this course continued to live for many years))) I introduced a new conversion of student currencies - peelmen/two bulbs