Creating new data frame using group by

Question

I'm having data frame like this:

cust_id   s1   s2 
  1      100   0
  2      100   1
  3      90    1
  4      85    0
  5      90    1

and I'm trying to get the following output:

 s1    s1(Count)  s2(sum)
 100     2          1
 90      2          2
 85      1          0

I tried to use groupby and size/sum (like in here: Pandas: Create a new Data Frame using multiple GroupBy results):

e.g., abc = df.groupby(by="s1")["s1","s2"].sum() ## I don't know how to create count for s1 and sum for s2

Your help will be appreciated!