0. Introduction 1. Statement of results 2. Proof of Theorem 0; the upper bound 3. Preliminaries 4. Proof of Theorem 1; the minor arcs estimate 5. Proof of Theorem 1; the major arcs estimate 6. Proof of Theorem 2; preliminaries 7. Proof of Theorem 2; completion 8. Proof of Propositions 1 and 2 9. Proof of Theorem 3