Is the following relation a function?

Two circles are shown, one labeled x and the other labeled y. The x circle contains the numbers 6, negative 2, 4, and negative 1. The y circle contains the numbers 2, negative 2, and 1. Arrows map numbers from x to numbers from y. There are arrows going from 6 to negative 2, from negative 2 to 2, from 4 to 1, and from negative 1 to 1.