19.1. In three boxes lie balls - black, white, and green (one ball in each box). On the first box, it says "white," on the second - "black," on the third "white or green." It is known that none of the inscriptions are true. Determine which balls are in which boxes.
19.1. The third box can contain only a black ball. A white ball can lie only in the second box. The green ball lies in the first box.