If a pair is located at a same point, say 36 coolers & 6 helmets, or gap, say 25 & 8, then such a pair is efficient. If both of the pair does not share the same gap or the same point then the pair is not efficient. If the two numbers of a pair are NOT located at the same point or gap because one of the numbers is not enough, say 35 & 5, then not having enough means inefficient. If both numbers of a pair are not in the same point or gap because one of the values is too large, say 37 & 7, then such is outside or beyond current possibilities