how to finish activity when user press back button
<p>I have 3 activities  activity1 activity2 and activity3
these are acreated in this manner</p>

<pre><code>         Activity1 is the launcher activity
                 Activity2 is created and started from activity1
                         activity3 is created and started from activity2
</code></pre>

<p>in activity 3(currently displayed)  and press back key on phone.
now i want to finish the activity(currently displayed activity ) when user press the back key of phone. </p>
