FATAL ERROR : main have you declared this activity in your AndroidManifest.xml?

FATAL ERROR : main have you declared this activity in your AndroidManifest.xml?

i don't know how to declared my activity. thank you. and this is my androidmanifest.xml

 <?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://ift.tt/nIICcg"
package="info.androidhive.slidingmenu"
android:versionCode="1"
android:versionName="1.0" >

<uses-sdk
    android:minSdkVersion="11"
    android:targetSdkVersion="17" />

<application
    android:allowBackup="true"
    android:icon="@drawable/ic_launcher"
    android:label="@string/app_name"
    android:theme="@style/AppTheme" >
    <activity
        android:name="info.androidhive.slidingmenu.MainActivity"
        android:label="@string/app_name" >
        <intent-filter>
            <action android:name="android.intent.action.MAIN" />

            <category android:name="android.intent.category.LAUNCHER" />
        </intent-filter>
    </activity>
</application>

where should i put declaration of my activity.