how to count number of states in sequence?

Suppose I have a sequence 1,3,3,1,2,1,4,2,3,1,4,2,4,4,4,3,1,2,5,1 in this 5 states are there, so how to count that there are 5 states.

Answer 1

[Azzi Abdelmalek]

a=[1,3,3,1,2,1,4,2,3,1,4,2,4,4,4,3,1,2,5,1]
out=unique(a)
number_of_states=numel(out)