A, B and C start running simultaneously from the points P, Q and R respectively on a circular track. The distance (when measured along the track) between any two of the three points P, Q and R is L and the ratio of the speeds of A, B and C is 1 : 2 : 3. If A and B run in opposite directions while B and C run in the same direction, what is the distance run by C before A , B and C meet for the first time?