Problem1025--The Triangle

1025: The Triangle

[Creator : ]
Time Limit : 1.000 sec  Memory Limit : 128 MiB

Description

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.
  • The number of rows in the triangle is >1 but ≤25.
  • The numbers in the triangle, all integers, are between 0 and 99.








Input

The first line of input will contain an integer N. The ith of the next N lines will contain i space-separated integers, denoting the values of the triangle.

Output

The highest sum as required by the problem statement.

Sample Input Copy

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

Sample Output Copy

30

Source/Category

IOI