This is my data frame

```
           Date    Name     Attempt   Count
0  2015-01-02    Adam       Yes      
1  2015-01-29    Adam       Yes      
2  2015-02-02    David      No       
3  2015-03-02    David      Yes      
4  2015-03-02    Hardik     Yes       
5  2015-03-02    David      No    

```

Now I need to count the number of attempts of a person month-wise. Want to count only if attempt value is 'yes' and insert the value in count column.

This is the expected output

```
           Date    Name     Attempt    Count
0  2015-01-02    Adam        Yes          2
1  2015-01-29    Adam        Yes          2
2  2015-02-02    David       No           0
3  2015-03-02    David       Yes          1
4  2015-03-02    Hardik      Yes          1 
5  2015-03-02    David       No           1

```