You have been hired at an open-air mine. You are to write a program to control a digger. For your task, you have been given a `map' of all the underground resources in the mine. This map comes as a file. The file has n rows. Each row has n space-separated integers. Each integer is between zero and one hundred (inclusive). The file should be understood to represent a grid, n wide by n deep. Each square in the grid can contain valuable resources. The value of these resources can go from zero (no resources) to 100 (max resources).

The grid maps the resources just below the surface, and down to the lowest diggable depths. The digger starts at the surface (so, just on top of the topmost row in the grid)at any horizontal position between 1 and n. The digger cannot dig directly downwards, but it can dig diagonally in either direction, left-down, or right-down. In its first time-step, it will dig onto the first row of the grid. In its second time-step, it'll hit the second row, and so on. When the digger reaches row number n, it has to be air-lifted out of the mine, and is no longer usable.

Every time the digger hits a square with resources in it, we can reclaim those resources.

Write a program that reads as a command-line argument a number n, this number is the number of columns and rows mentioned above.

It then reads from standard input n * n integers, each integer being between zero (0) and one hundred (100), and then writes to standard out a single integer representing the maximum possible profit