#include <stdio.h>

int next[100010];
int find(int k)
{
	if(next[k]==k) return k;
	else return next[k] = find(next[k]);
}

int A[100010],B[100010];
double P[100010];
int check[100010];

int main()
{
	int a;
	scanf("%d",&a);
	for(int i=1;i<=a;i++) scanf("%d",&A[i]);
	for(int i=1;i<=a;i++) scanf("%d",&B[i]);
	for(int i=1;i<=a;i++)
	{
		int c;
		scanf("%d",&c);
		if(c==0) check[i] = 1;
		else P[i] = (double)1/(2*c);
	}
	
	double sum = 0;
	for(int i=1;i<=a;i++) next[i] = i;
	for(int i=1;i<=a;i++)
	{
		if(check[i]==0)
		{
			double lambda = (A[i]-B[i])/P[i];
			sum += (lambda*lambda*P[i])/2;
		}
	}
	
	int b;
	scanf("%d",&b);
	for(int i=1;i<=b;i++)
	{
		int c,d;
		scanf("%d%d",&c,&d);
		c = find(c);
		d = find(d);
		if(c!=d)
		{
			double lambda;
			if(check[c]==1&&check[d]==1);
			else if(check[c]==1)
			{
				lambda = (A[d]-B[d])/(P[d]);
				sum -= (lambda * lambda * P[d])/2;
				next[c] = d;
				check[d] = 1;
			}
			else if(check[d]==1)
			{
				lambda = (A[c]-B[c])/(P[c]);
				sum -= (lambda * lambda * P[c])/2;
				next[c] = d;
			}
			else
			{
				lambda = (A[c]-B[c])/(P[c]);
				sum -= (lambda * lambda * P[c])/2;
				lambda = (A[d]-B[d])/(P[d]);
				sum -= (lambda * lambda * P[d])/2;
				
				next[c] = d;
				A[d] += A[c];
				B[d] += B[c];
				P[d] += P[c];
				
				lambda = (A[d]-B[d])/(P[d]);
				sum += (lambda * lambda * P[d])/2;
			}
		}
		printf("%.12lf\n",sum);
	}
}