LEAN_INFORMATION
position 18:6
a b c d : ℕ,
h₁ : a + b = 0,
h₂ : b = 0,
aeq0 : a = 0,
h₃ : succ c = 1,
h₄ : d = c - 1
⊢ c = 0
END_LEAN_INFORMATION