Getting the correct sex count from a View
11:52 03 Mar 2023

I have a view results like this:

Teacher_id Sex Missed_Day
45 m 19-01-2023
37 f 19-01-2023
45 m 01-02-2023
78 m 01-02-2023

I would like a SELECT count(Sex) to give me results as follows as the Teacher_id = 45 is a duplicate so it is one male not two:

Male Female
2 1

Currently I am having this :

COUNT(DISTINCT CASE WHEN Sex = 'm' THEN 1 END) AS Male, 
COUNT(CASE WHEN Sex = 'f' THEN 1 END) AS Female
Male Female
3 1

How do I write this query to give me the desired results by not counting sex twice of Teacher_id

sql-server count sql-server-2016