func commonPrimeDivisors(a, b []int) int {
	var gcd func(n, m int) int
	gcd = func(n, m int) int {
		if n%m == 0 {
			return m
		}

		return gcd(m, n%m)
	}

	removeCommonPrimeDivisors := func(n, m int) int {
		for n != 1 {
			d := gcd(n, m)
			if d == 1 {
				break
			}
			n /= d
		}

		return n
	}

	counter := 0
	for i := range a {
		x, y := a[i], b[i]
		d := gcd(x, y)

		x = removeCommonPrimeDivisors(x, d)
		if x != 1 {
			continue
		}

		y = removeCommonPrimeDivisors(y, d)
		if y == 1 {
			counter++
		}
	}

	return counter
}