KEX13(A)B B B B,KEY TRAPPED EXCHANGE UNIT
KEX13(A)B B C C,KEY TRAPPED EXCHANGE UNIT
KEX13(A)B C D D,KEY TRAPPED EXCHANGE UNIT
KEX13(A)B C D E,KEY TRAPPED EXCHANGE UNIT
KEX13(B)C C C C,KEY TRAPPED EXCHANGE UNIT
KEX13(C)D D D D,KEY TRAPPED EXCHANGE UNIT
KEX13(D)E E E E,KEY TRAPPED EXCHANGE UNIT
KEX13(D)E E F F,KEY TRAPPED EXCHANGE UNIT
