exact this
ℕ : Type
inst✝³ : Core ℕ
inst✝² : Induction ℕ
inst✝¹ : Addition ℕ
inst✝ : Sign ℕ
order_inst : Order ℕ
n m k : ℕ
x✝¹ : n ≤ m
x✝ : m < k
this✝ : n < m ∨ n ≃ m
h✝ : n < m
this : n < k
⊢ n < k
no goals