Among the pairs of genes that are not from the class of motorproteins, how many of them are negatively correlated?
If Expression_Corr < 0, it means the negatively correlated
SELECT COUNT(T1.GeneID) FROM Genes AS T1 INNER JOIN Interactions AS T2 ON T1.GeneID = T2.GeneID1 WHERE T2.Expression_Corr < 0 AND T1.Class = 'Motorproteins'