A project has four activities $P, Q, R$ and $S$ as shown below.

$$\begin{array}{|c|c|c|c|} \hline \text{Activity} & \text{Normal duration (days)} & \text{Predecessor} & \text{Cost slope (Rs./day)} \\ \hline P & 3 & – & 500 \\ \hline Q & 7 & P & 100 \\ \hline R & 4 & P & 400 \\ \hline S & 5 & R & 200 \\ \hline \end{array}$$

The normal cost of the project is Rs. $10,000$/- and the overhead cost is Rs. $200$/- per day. If the project duration has to be crashed down to $9$ days, the total cost (in Rupees) of the project is _______