Python multiplication error
<p>I making a program in which a single line of input containing an integer, print a triangle of asterisks of that size. But my program is not working like this. So can you please have a look on my code and can determine my mistake please. Thanks</p>

<pre><code>line = int(raw_input("Number of lines: "))
a = line * '*'
print a
</code></pre>

<p>This is the output I want to produce: </p>

<pre><code>Number of lines: 5
*
**
***
****
*****
</code></pre>
