program common1
  implicit none

  common /block/ aaa, bbb, ccc
  integer :: aaa
  real :: bbb
  double precision :: ccc

  aaa = 5
  bbb = 4.6
  ccc = 2.345
  print *, aaa, bbb, ccc

  call helper
  print *, aaa, bbb, ccc
end program common1

subroutine helper
  implicit none
  common /block/ aaa, bbb
  integer :: aaa
  real :: bbb
  
  aaa = 50
  bbb = 40.6
end subroutine helper