Winter in Yekaterinburg is the longest time of the year. And everyone
spends long winter evenings in his own way. For example, Eugene creates
computer games in the evenings. His current game has a very simple game
play — user controls a spaceship flying in 3D space. To test the
mechanics of the movement of his spaceship Eugene wants to solve
the following problem: can his spaceship, moving in a straight line, fly
through the points A and B, then make a turn at 90°, and
then fly through the points C and D, continuing to move in a straight
line. The points A, B, C, D should be visited by the spaceship in
just that order, the turning point may coincide with the point B or the
point C. The spaceship should be considered as a material point.
Input
There are four lines, each containing integers x_{i}, y_{i}, z_{i} that
are the coordinates of the points A, B, C, D respectively (−10^{6}
≤ x_{i}, y_{i}, z_{i} ≤ 10^{6}). All points are pairwise
different.
Output
If the spaceship can fly through the data points, output “Valid”,
otherwise output “Invalid”.
Sample
input  output 

2 0 0
1 0 0
0 1 0
0 2 0
 Valid

Problem Author: Denis Dublennykh
Problem Source: Open Ural FU Personal Contest 2014