F′ ← |1 memo(⨬(+⊃(F′-1|F′-2)|◌1)⊸<₂)
F  ← F′⌵
F¯10

F ← (
  F′ ← |1 memo(⨬(+⊃(F′-1|F′-2)|◌1)⊸<₂)
  F′⌵
)
F¯10