q.Nat().SubOne(q) // lcm(a, b) = a×b / gcd(a, b) = a × (b / gcd(a, b)) // Our GCD requires at least one of the numbers to be odd. For LCM we only // need to preserve the larger prime power of each prime factor, so we can // right-shift the number with the fewest trailing zeros until it's odd. // For odd a, b and m >= n, lcm(a×2ᵐ, b×2ⁿ) = lcm(a×2ᵐ, b). az, bz := a.TrailingZeroBitsVarT(), b.TrailingZeroBitsVarT() if az < bz { a = a.ShiftRightVarTime(az) } else { b = b.ShiftRightVarTime(bz) } gcd, err := bi...