
Willson the Canada Goose is like any other Canada Goose - he can be territorial at times, especially to unfamiliar geese and unsuspecting humans.
Having just arrived in California for the first time, Willson's family decides to rest at the point
Willson can only waddle horizontally or vertically. He determines that his territory consists of any point that requires no more than
Willson wants to know the area of his territory, so he knows how much "territorial markings" he will need to use. Can you help him?
Input Specification
The first line of input will contain two space-separated integers,
The next line of input will contain a single integer,
All coordinates
Output Specification
Output a single integer, the area of Willson's territory. If your answer is not an integer, round it to the nearest one.
Sample Input
0 1
4
1 1
2 1
1 0
1 -1
Sample Output
18
Comments
where is 'k' in the input?
It isn't directly in the input, but implied.