day1 ⇐ {
  nums ← •BQN⎊0¨ •FLines "input/day1"
  sums ← ∨ (+´ {𝕩↑𝕨↓nums}´)¨ (»⋈¨ ⊢-») / 0⊸≡¨ nums

  a ⇐ ⊑sums ⋄ b ⇐ +´ 3↑sums
}