  Contribution of order \alpha^2 (Z \alpha)^6 \ln^3(Z \alpha)^{-2} to the
ground-state Lamb shift in hydrogen induced by the loop-after-loop diagram is
evaluated analytically. An additional contribution of this order is found
compared to the previous calculation by Karshenboim [JETP 76, 541 (1993)]. As a
result, an agreement is achieved for this correction between different
numerical and analytical methods.
