def leading
import bend-collections@1.0.0.0/src/crypto/blake/blake2s/blake2s.bend as Blake2simport Base
175# Blocks before the last one: max(1, ceil(length/64)) - 1.
176def leading(length: Nat) -> Nat:
177 Nat.sub(Nat.div(Nat.add(length,63n),64n),1n)