The given code is calculating the maximum sum of a path in a triangle of numbers. The input consists of an integer n, followed by n lines of numbers representing the triangle. Each line contains i numbers, where i ranges from 1 to n.

The code first reads the input and stores it in a two-dimensional array a. Then, it iterates through the array from the second-to-last row to the first row. In each iteration, it calculates the maximum sum of the current number and the maximum sum of the two adjacent numbers in the row below. This sum is then stored in the current position in the array.

Finally, the code outputs the maximum sum at the top of the triangle, which is stored in a[1][1].

Note: The code assumes that the input triangle has at least one row and the numbers in each row are non-negative.