#include<iostream>
using namespace std;
struct fountain
{
       int p,q;
};
class Hall_of_Fountains
{
      public:
             bool input();
      private:
              bool DFS(int);
              bool _right(int,int);
              bool stay(int,int);
			  bool _left(int,int);
              fountain num[101];
              int n,                   //喷泉个数
				  count_num,           //房间序号
				  count;               //计数
};
bool Hall_of_Fountains::input()
{
     scanf("%d",&n);
     if(n==0)return false;
	 num[0].p=0;
	 num[0].q=0;
     for(int i=1;i<=n;i++)
     {
             scanf("%d",&num[i].p);
     }
      for(int i1=1;i1<=n;i1++)
     {
             scanf("%d",&num[i1].q);
     }
     count_num=0;
	 count=0;
     DFS(0);
     return true;
}
bool Hall_of_Fountains::_right(int a,int k)   //前进
{
     int k1=num[a+1].q-1;
     int k2=num[a+1].q+num[a+1].p;
     if(num[a+1].p==0)return true;
     int i=(k-num[a+1].q)/num[a+1].p;
     if(i%2!=0)i=i+1;
     if(k1+i*num[a+1].p<=k&&k<k2-1+i*num[a+1].p)
         return false;
     return true;
}
bool Hall_of_Fountains::stay(int a,int k)    //原地
{
     int k1=num[a].q-1;
     int k2=num[a].q+num[a].p;
     if(num[a].p==0)return true;
     int i=(k-num[a].q)/num[a].p;
     if(i%2!=0)i=i+1;
     if(k1+i*num[a].p<=k&&k<k2-1+i*num[a].p)
         return false;
     return true;
}
bool Hall_of_Fountains::_left(int a,int k)   //后退
{
	 if(a==0)return false;
	 int k1=num[a-1].q-1;
	 int k2=num[a-1].q+num[a-1].p;
	 if(num[a-1].p==0)return true;
	 int i=(k-num[a-1].q)/num[a-1].p;
	 if(i%2!=0)i=i+1;
     if(k1+i*num[a-1].p<=k&&k<k2-1+i*num[a-1].p)
         return false;
	 return true;
}
bool Hall_of_Fountains::DFS(int k)    //深度搜索
{
	 count++;
     if(count>=5000)               //是不是这有问题，最大时间能多少呀
     {
          printf("0\n");
          return true;
     }
     if(count_num==n)
     {
          printf("%d\n",k+1);
          return true;
     }
     if(_right(count_num,k))
     {
          count_num++;
		  k=k+1;
          if(DFS(k))return true;
		  k=k-1;
          count_num--;
     }
     if(stay(count_num,k))
     {
		  k=k+1;
          if(DFS(k))return true;
		  k=k-1;
     }
     if(_left(count_num,k))
     {
          count_num--;
		  k=k+1;
          if(DFS(k))return true;
		  k=k-1;
          count_num++;
     }
     return false;
}
int main()
{
    while(1)
    {
        Hall_of_Fountains bb;
        if(!bb.input()) return 0;     
    }
}