program summor
  implicit none

  integer ::  k
  real    ::  summa

  summa = 0.0
  do k = 1, 1000000
    summa = summa + 1.0 / real(k)
  end do

  print"(a, f9.6)", "1 + 1/2 + ... + 1/1000000 = ", summa

  summa = 0.0
  do k = 1000000, 1, -1
    summa = summa + 1.0 / real(k)
  end do
  
  print"(a, f9.6)", "1/1000000 + ... + 1/2 + 1 = ", summa

end program summor