  We show that the sum over planar trees formula of Kontsevich and Soibelman
transfers C-infinity structures along a contraction. Applying this result to a
cosimplicial commutative algebra A^* over a field of characteristic zero, we
exhibit a canonical unital C-infinity structure on Tot(A^*), which is unital if
A^* is; in particular, we obtain a canonical C-infinity structure on the
cochain complex of a simplicial set.
