4
ABCD EFGH even
ABCI EFJK up
ABIJ EFGH even
ABC DEF up
GHI JKL even
EF DA up
ABCDEF GHIJKL up
ABC DEF even
I J down
ABC DEJ down
ACH IEF down
AHK IDJ down
K is the counterfeit coin and it is light.
D is the counterfeit coin and it is light.
I is the counterfeit coin and it is light.
A is the counterfeit coin and it is light.
若某枚 X 是counterfeit的哪枚, 必定出現在 up 或 down 的資料列中
但 出現在 even 或 (可能 light 又 可能 heavy )的 可以排除