Towards size reconstruction from fewer cards

It is proved that if two graphs of order nn have n−pn−p cards (vertex-deleted subgraphs) in common, where p⩾3p⩾3, and nn is large enough compared with pp, then the numbers of edges in the two graphs differ by at most p−2p−2. This is a modest but nontrivial improvement of the easy result that these numbers differ by at most pp.