Dihedral angle is the angle between two intersecting planes. Considering two planes  and , we name the intersection line of the two planes as , a point on  to be , and a point on  to be , then we can describe one dihedral angle between  and  to be dihedral angle  or . In addtion, the range of dihedral angles is  which differs dihedral angle from the smallest angle between two planes whose range is .

Now, given the  coordinates of four points  and , your task is to calculate the degree of dihedral angle .

Here we provide a formula of dihedral angle which might be useful, and we assume  to be the normal vector of plane , which is a vector perpendicular to the plane .

输入描述:

The first line contains three integers , the  coordinates for point .

The second line contains three integers , the  coordinates for point .

The third line contains three integers , the  coordinates for point .

The fourth line contains three integers , the  coordinates for point .

It is also guarenteed that all the coordinates are in range [ ], and none of the points have same  coordinates.

输出描述:

Please output the degree of dihedral angle  after rounding.

1 0 2
0 0 0
2 0 0
1 2 0

90

0 -1 1
0 0 0
2 0 0
1 2 0

135

备注:

About rounding：
If the first digit after the decimal point is less than 5, round the number you're considering down.
If the first digit after the decimal point is more or equal to 5, round the number you're considering up.