#include <stdio.h>
#include <math.h>
int n,i,w[500010],xx[500010],yy[500010],e,t[1000000],min;
void dfs(long long x,long long y)
{
	if(x>1000000)  return;
	if(y>1000000)
	{
		memset(t,0,sizeof(t));
		dfs(x+1,0);
		return;
	}
	
	for(i=1;i<=n;i++)
		t[y]+=w[i]*(abs(x-xx[i])+abs(y-yy[i]));
	if(min>t[y])
		min=t[y];
	dfs(x,y+1);
}
int main()
{
	freopen("ballc.in","r",stdin);
	freopen("ballc.out","w",stdout);
	scanf("%d",&n);
	for(i=1;i<=n;i++)  scanf("%d",w+i);
	for(i=1;i<=n;i++)  scanf("%d %d",xx+i,yy+i);
	memset(t,0,sizeof(t));
	min=0x3f3f3f3f;
    dfs(0,0);
	printf("%d.00",min);
	return 0;	
}