- Time limit: 3.00 s
- Memory limit: 512 MB
Uolevi is working at a giant megacorporation's warehouse. Now that he has stacked all the boxes that contain items, he is going to build the tallest possible pyramid from the empty boxes. There are n boxes numbered 1,2,\dots,n, the i-th of which has width x_i, depth y_i, and height z_i. A tower of boxes is called a pyramid if x_i \leq x_j and y_i \leq y_j holds for all pairs of boxes (i, j) where box i is on top of box j. Find the height of the tallest possible pyramid Uolevi can construct.
Input
The first line contains a single integer n. The i-th of the next n lines contains three integers x_i, y_i, and z_i.
Output
Print the height of the tallest possible pyramid.
Constraints
- 1 \leq n \leq 2 \times 10^5
- 1 \leq x_i, y_i, z_i \leq 10^9
Example 1
Input:
5 5 10 8 10 1 2 4 10 2 3 1 4 2 4 4
Output:
14
Example 2
Input:
10 5 2 1 10 6 10 5 5 5 4 4 2 3 7 7 2 3 5 3 7 7 9 6 7 2 5 6 6 2 8
Output:
33
Example 3
Input:
1 1000000000 1000000000 1000000000
Output:
1000000000
