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 centosRUN \  yum update -y && \  yum install vsftpd -y EXPOSE 21CMD 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 configurationquestions will narrow this down by presenting a list of cities, representingthe 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. USGeographic 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?