Please solve this

In an experiment in which a single dice is thrown n times, let's say that there is a point P that starts from the origin and moves over a vertical line depending on the number of eyes of the thrown dice. It is said that point P moves by 1 in the positive direction if 4 or less than 4 eyes come out by throwing the dice, and point P moves by 1 in the negative direction if 5 or more than 5 eyes come out. Let the random variable X denote the number of times 4 or less than 4 eyes appear, and let the random variable Y denote the coordinate of P. Find R_X and f_X, and use it to nd the expected value of Y. (R_X denotes the image of X and f_X denotes the probability mass/density function of X)