If you want to build something using a Raspberry Pi, you'll probably use resistors. 
For this exercise, you need to know two things about them:
<ul>
<li>Each resistor has a resistance value.</li>
<li>Resistors are small - so small in fact that if you printed the resistance value on them, it would be hard to read.</li>
</ul>
To get around this problem, manufacturers print color-coded bands onto the resistors to denote their resistance values. 
Each band has a position and a numeric value.
The first 2 bands of a resistor have a simple encoding scheme: each color maps to a single number. 
For example, if they printed a brown band (value 1) followed by a green band (value 5), it would translate to the number 15.
In this exercise you are going to create a helpful program so that you don't have to remember the values of the bands. 
The program will take color names as input and output a two digit number, even if the input is more than two colors!
The band colors are encoded as follows:
<ul>
<li>Black: 0</li>
<li>Brown: 1</li>
<li>Red: 2</li>
<li>Orange: 3</li>
<li>Yellow: 4</li>
<li>Green: 5</li>
<li>Blue: 6</li>
<li>Violet: 7</li>
<li>Grey: 8</li>
<li>White: 9</li>
</ul>
From the example above: 
brown-green should return 15 
brown-green-violet should return 15 too, ignoring the third color.

Resistor Color Duo