Let \( A=\{0,3,4,6,7,8,9,10\} \) and \( R \) be the relation defined on \( A \) such that \( R=\{(x,y)\in A\times A:x-y \text{ is odd positive integer or } x-y=2\} \). The minimum number of elements that must be added to the relation \( R \), so that it is a symmetric relation, is equal to ________.
