WORST_CASE(?,O(n^2))

Solution:
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  "append" :: ["b"(1, 0) x "b"(0, 0)] -(1)-> "b"(0, 0)
  "attach" :: ["a"(0, 0) x "b"(2, 0)] -(1)-> "b"(1, 0)
  "cons" :: ["a"(0, 0) x "b"(1, 0)] -(1)-> "b"(1, 0)
  "cons" :: ["a"(0, 0) x "b"(2, 0)] -(2)-> "b"(2, 0)
  "cons" :: ["a"(0, 0) x "b"(5, 2)] -(3)-> "b"(3, 2)
  "cons" :: ["a"(0, 0) x "b"(0, 0)] -(0)-> "b"(0, 0)
  "nil" :: [] -(0)-> "b"(1, 0)
  "nil" :: [] -(0)-> "b"(2, 0)
  "nil" :: [] -(0)-> "b"(3, 2)
  "nil" :: [] -(0)-> "b"(0, 0)
  "pair" :: ["a"(0, 0) x "a"(0, 0)] -(0)-> "a"(0, 0)
  "pairs" :: ["b"(3, 2)] -(1)-> "b"(0, 0)


Cost Free Signatures:
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