user creation problem in redhat7.2/9.0-like----- 40yoga

[yogesh at banasdairy.coop]

hi friends
i have a mail server on rh 7.2/9.0

i wnat to create user with username like ----40yoga

when i creste
shell#useradd 40yoga
invalid username '40yoga'
shell#


can any one give me soluction about that one i emergeny require
to crete user like this


so please help me came out my problem


thanks and regards
Yogesh M Chaudhari
Banasdairy
palanpur