Let OP = ((α − 1)/α)î + ĵ + k^, OQ = î + ((β − 1)/β)ĵ + k^ and OR = î + ĵ + (1/2)k^ be three vectors, where α, β ∈ ℝ − {0} and O denotes the origin. If (OP × OQ) · OR = 0 and the point (α, β, 2) lies on the plane 3x + 3y − z + l = 0, then the value of l is ________.