What $is$ the acute angle between the lines

$l_1$:vec$(r)(t)=($:$-8,5,-2$:$)+t($:$1,-2,4$:$)$

and

$l_2$:vec$(R)(u)=($:$-8,1,-3$:$)+u($:$-2,1,-3$:$)$

Give your answer $in$ radians, rounded $toat$ least three decimal places.

Angle $=$

radians.