This sequence works like a small word game: each new term describes groups of digits from the previous one. Write a function count_and_say that returns the n-th term of the sequence. The first term is 1, and after that each run of equal digits becomes a pair: how many digits there are and which digit it is. For example, 21 becomes 1211: one 2 and one 1.

def count_and_say(n: int) -> str: