if-statement: Count number of terms of individual take the leaderboard

I'm searching a solution that can be accomplished use the basic function provided by Excel/Google sheet (without touching vba).

The problem is this, I'm building some sort of record of a leaderboard.

Given the column A recording who is the leader X in that week.
I want some naive formula in column B able to tell me this the n-th term of X as leader
Column C will have formula counting this is the m-th week in X's current term.

Given (Term) (Week) Explanation

A 1 1 That is A's first term as leader, the first week in his first term

A 1 2 That is A's first term as leader, the second week in his first term

A 1 3 That is A's first term as leader, the third week in his first term

B 1 1 That is B's first term as leader, the first week in his first term

B 1 2 That is B's first term as leader, the second week in his first term

C 1 1 That is C's first term as leader, the first week in his first term

A 2 1 That is A's second term as leader, the first week in his second term

A 2 2 That is A's second term as leader, the second week in his second term

A 2 3 That is A's second term as leader, the third week in his second term

A 2 4 That is A's second term as leader, the fourth week in his second term

D 1 1 That is A's first term as leader, the first week in his first term

if-statement