Madison, is a little girl who is fond of toys. Her friend Mason works in a toy manufacturing factory . Mason has a 2D board of size with rows and columns. The board is divided into cells of size with each cell indicated by it's coordinate . The cell has an integer written on it. To create the toy Mason stacks number of cubes of size on the cell .
Given the description of the board showing the values of and that the price of the toy is equal to the 3d surface area find the price of the toy.
The first line contains two space-separated integers and the height and the width of the board respectively.
The next lines contains space separated integers. The integer in line denotes .
Print the required answer, i.e the price of the toy, in one line.
Sample Input 0
Sample Output 0
The surface area of cube is 6.
Sample Input 1
3 31 3 42 2 31 2 4
Sample Output 1
The sample input corresponds to the figure described in problem statement.