Conditional probability: rains on $4^{th}$ day if $1^{st}$ day is a rainy day?

Question

{Probability of a day being a rainy day only depends on the day before}. If yesterday was a rainy day then there is $0.6$ percent chance that today will be a rainy day and if yesterday was a sunny day probability of today being a rainy day is $0.4$.
Then what is the probability that the $4^{th}$ day is a rainy day if the $1^{st}$ day was a rainy day? This is my first question in this site please forgive me for making mistakes in the format of writing question.

Answer 1

Using WW1's method

RRRR + RSRR + RRSR + RSSR

$$(1)(.6)(.6)(.6) + (1)(.4)(.4)(.6) + (1)(.6)(.4)(.4) + (1)(.4)(.6)(.4)= 0.504$$

Assuming the only weather types are sunny and rainy