// all the ellipses sizes.
func getDivisibleSize(totalSizes []uint64) (result uint64) {
	gcd := func(x, y uint64) uint64 {
		for y != 0 {
			x, y = y, x%y
		}
		return x
	}
	result = totalSizes[0]
	for i := 1; i < len(totalSizes); i++ {
		result = gcd(result, totalSizes[i])
	}
	return result
}

// isValidSetSize - checks whether given count is a valid set size for erasure coding.