If the equation of the plane containing the line
\[
\vec r=\hat i+2\hat j+\hat k+t(\hat i-\hat j+2\hat k)
\]
and parallel to the line
\[
\vec r=-\hat i+2\hat j+s(-\hat i+2\hat j+\hat k)
\]
in Cartesian coordinates is
\[
\frac{x}{a}+\frac{y}{b}+\frac{z}{c}=1,
\]
then \(a+3b+c=\)
Show Hint
If a plane contains one line and is parallel to another line, use the direction vectors of both lines to obtain the normal vector through their cross product.