Travelling by car
There are cities. You want to travel from city to city by car. To do this you have to buy some gasoline. It is known that a liter of gasoline costs in the -th city. Initially your fuel tank is empty and you spend one liter of gasoline per kilometer. Cities are located on the same line in ascending order with -th city having coordinate . Also you have to pay to enter -th city. Your task is to make the trip with minimum possible cost.
Input
First line contains number of cities .
Second line contains coordinates of cities . Coordinates are unique and sorted, for each .
Third line contains integers — the gasoline costs .
Fourth line contains integers — the entrance payments .
Its is knows that cities coordinates, gasoline costs and entrance payments are nonnegative integers, not greater than .
Output
Print the minimum possible cost to make the trip.