program summor
      implicit none

      integer  k
      real     summa

      summa = 0.0
      do 10 k = 1, 1000000
        summa = summa + 1.0 / real(k)
10    continue 

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

      summa = 0.0
      do 20 k = 1000000, 1, -1
        summa = summa + 1.0 / real(k)
20    continue 

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

      end