When M<=H, enumerate all 2^M assignments to the leaf wires. For each assignment evaluate the vertex entries from their creation-time descriptions, use their fixed coordinate representatives, multiply them modulo the call precision, and add to a running accumulator. An isolated vertex contributes its scalar; an empty network contributes one. This is exact direct contraction, so it supplies the base case without another recursive assumption. Only the current wire assignment, one product and one sum need be retained. The entry cost is still measured against root s, not the smaller leaf M.