Let \( A=\{1,4,7\} \) and \( B=\{2,3,8\} \). Then the number of elements, in the relation \( R=\{((a_{1},b_{1}),(a_{2},b_{2}))\in(A\times B)\times(A\times B):a_{1}+b_{2}\text{ divides }a_{2}+b_{1}\} \) is ______________ .