ab ac ad ae af ag ah ai aj
bc bd be bf bg bh bi bj
cd ce cf cg ch ci cj
De df dg dh di dj
ef eg eh ei ej
Fiber, fiber, fiber.
gh gi gj
Hi hj
In the neck
If there are 405 people, in theory, there can be 9 people to choose from in each situation. There is no guarantee that no less than 65,438+00 voters will vote for the same two candidates. If there are 406 people, it can be guaranteed.