Mathematics

Problem

Let

A = \{-4, -3, -2, 0, 1, 3, 4\}

and

R = \{(a, b) \in A \times A : b = |a|

b^2 = a + 1\}

be a relation on

A

. Then the minimum number of elements, that must be added to the relation

R

so that it becomes reflexive and symmetric, is _____.