Description

7
3   8
8   1   0
2   7   4   4
4   5   2   6   5
(Figure 1)

Input

Your program is to read from standard input. The first line contains one integer N: the number of rows in the triangle. The following N lines describe the data of the triangle. The number of rows in the triangle is > 1 but <= 100. The numbers in the triangle, all integers, are between 0 and 99.

Output

Your program is to write to standard output. The highest sum is written as an integer.

5
7
3 8
8 1 0 
2 7 4 4
4 5 2 6 5

30

Source

IOI 1994