I wrote this below code , but the output contained both M and F.   I did not got the logic

please add parenthesis around (first_name='kellie' or first_name='Denis')

you should add parenthesis to the OR condition

Hi everyone!
Thanks for reaching out.

@: Hend
As Zubair and Yumna said you should use parenthesis to the OR condition.

Hope this helps.
Best,
Tsvetelin