@Q:
  RETURN LENGTH(
    FOR v IN OUTBOUND
      SHORTEST_PATH <span class="hljs-string">"mps_verts/A"</span> TO <span class="hljs-string">"mps_verts/C"</span> mps_edges
        RETURN v
  )   

@R
[
  <span class="hljs-number">3</span>
]