# The Triangle

Time Limit: 1000MS

Memory Limit: 10000K

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## Description

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

(Figure 1)
Figure 1 shows a number triangle. Write a program that calculates the highest sum of numbers passed on a route that starts at the top and ends somewhere on the base. Each step can go either diagonally down to the left or diagonally down to the right.

## 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.

## Sample Input

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

## Sample Output

30

N/A