Unable to build Image as it is asking some input

I am trying to create an Image which will run ftp server on centos. Dockerfile content is as below:

FROM centos
 
RUN 
  yum update -y && 
  yum install vsftpd -y 
 
EXPOSE 21
CMD vsftpd -DFOREGROUN

I am running below command :

docker build -f webserver .

which is asking me input as below:

Please select the geographic area in which you live. Subsequent configuration
questions will narrow this down by presenting a list of cities, representing
the time zones in which they are located.
 
  1. Africa      4. Australia  7. Atlantic  10. Pacific  13. Etc
  2. America     5. Arctic     8. Europe    11. SystemV
  3. Antarctica  6. Asia       9. Indian    12. US
Geographic area: 9

once I enter 9 and press enter button, it stuck at the same window. Can you please help me, how should I process this?