#include<stdio.h>
double a[100005];
double left_min[100005], right_max[100005];
int A[100005], B[100005];
long long int sa[100005], sb[100005];
int main()
{
	int n;
	scanf("%d", &n);
	int i, j;
	for (i = 0; i < n; i++)
		scanf("%d", &A[i]);
	for (i = 0; i < n; i++)
		scanf("%d", &B[i]);
	sa[0] = sb[0] = 0;
	for (i = 0; i < n; i++)
		sa[i + 1] = sa[i] + A[i];
	for (i = 0; i < n; i++)
		sb[i + 1] = sb[i] + B[i];
	double min, mid, max;
	min = 0;
	max = 1e18;
	int f;
	for (j = 0; j < 200; j++)
	{
		mid = (max + min) / 2;
		for (i = 0; i <= n; i++)
			a[i] = sa[i] - sb[i] * mid;
		left_min[0] = a[0];
		for (i = 1; i <= n; i++)
		{
			if (left_min[i - 1] > a[i])
				left_min[i] = a[i];
			else
				left_min[i] = left_min[i - 1];
		}
		right_max[n] = a[n];
		for (i = n - 1; i >= 0; i--)
		{
			if (right_max[i + 1] < a[i])
				right_max[i] = a[i];
			else
				right_max[i] = right_max[i + 1];
		}
		f = 0;
		for (i = 0; i < n; i++)
			if (left_min[i] > right_max[i + 1])
				f++;
		if (f > 0)
			max = mid;
		else
			min = mid;
	}
	printf("%.20lf\n", min);
	return 0;
}