program therefore
 implicit none
 character s*10,t*11
 integer a,b,c
 read *, s
 read *, t
 
 b = len_trim(s)
 c = len_trim(t)
 if ( c-b == 1 .and. s== t(:b) ) then
 print *,"Yes"
 else
 print *,"No"
 end if
end program therefore
 
