Let two straight lines drawn from the origin \( O \) intersect the line \( 3x + 4y = 12 \) at the point \( P \) and \( Q \) such that \( \triangle OPQ \) is an isosceles triangle and \( \angle POQ = 90^\circ \). If \( l = OP^2 + PQ^2 + OQ^2 \), then the greatest integer less than or equal to \( l \) is:
