Consider a uniprocessor system executing three tasks $A,B$ and $C$ each of which is composed of a sequence of instances as given below:
- $A: 3$ instances of $2\;\text{ms}$ task arriving at intervals of $5\;\text{ms},$ and $1\;\text{ms}.$
- $B: 4$ instances of $3\;\text{ms}$ task arriving at intervals of $2\;\text{ms}, 1\;\text{ms}$ and $3\;\text{ms}.$
- $C: 1$ instance of $5\;\text{ms}$ task.
The priority of each task is the inverse of its period, and the available tasks are scheduled in order of priority, which is the highest priority task scheduled first. Given that all tasks initially arrive at the beginning of the $1^{\text{st}}$ millisecond and task preemptions are allowed, the first instance of $C$ completes its execution at the end of _________ milliseconds.