How to bring the week as well with the month in pandas dataframe?

Question

Input:

df = pd.DataFrame({"Month":["Jan","Jan","Jan","Jan","Feb","Feb","Feb","Mar"],
                   "Week": [1,2,3,4,1,2,3,2],
                   "Sales":[1000,50,200,300,250,150,100,300]})

Given a sales dataframe, how to get the given op Output:

summary_df = pd.DataFrame({"Month":["Jan","Feb","Mar"],
                   "Week": [1,1,2],
                   "Sales":[1000,250,300]})

I have tried the following,

df.groupby(by=['Month']).agg({'Sales':'max'})

and got the output as,

|Month|Sales|
|---|---|
|Feb|250|
|Jan|1000|
|Mar|300|