Summarise and calculate the items specifically in the dataset using proc sql

My dataset and attempt

data mydata;
input Category $ Item $;
datalines;
A 1
A 1 
A 2
B 3
B 1
;

proc sql;
create table mytable as 
    select *, count(Category) as Total_No_in_Category, count(Category)-count(item, "3") as No_of_not_3_in_the_same_category from mydata
    group by Category;
run;

Result

Category     No_of_not_3_in_the_same_category   Total_No_in_Category


  A                      3                          3
  A                      3                          3
  A                      3                          3
  B                      2                          2
  B                      2                          1

My expected result

 Category   No_of_not_3_in_the_same_ category   Total_No_in_Category
    A                          2                       3
    B                          1                       2

I wonder how to achieve the expected result using only proc SQL. Thank you so much.