int sum(int a)
{
	int b;
	int he = 0;
	int arr[100] = { 0 };
	for (b = 0; a != 0;b++)
	{
		arr[b] = a % 10;
		a /= 10;
		he += arr[b];
	}

	if (he % 5 == 0)
	{
		return 1;
	}
	else
	{
		return 0;
	}
}

int main()
{
	int a, b,c,d;
	int e = 0;
	scanf("%d%d", &a, &b);

	for (c = a; c <= b; c++)
	{
		d = sum(c);
		if (d == 1)
		{
			e++;
		}
	}
	printf("%d\n", e);
	return 0;
}