prepare a program to find out the electricity bill. The rates of electricity per unit are as follows:
1. If the units consumed are equal or less than 100, then the cost is Rs 8/- per unit.
2. If the units consumed are more than 100 and less than and equal to 300, then the cost is Rs 10/- per unit and surcharge of 5% of bill is added.
3. If the units consumed are more than 300 and less than and equal to 500, then the cost is Rs 12/- per unit and surcharge of 15% of bill is added.
4. If the units consumed are more than 500, then the cost is Rs 15/- per unit and surcharge of 25% of bill is added.