Do you Know? How to Align top of one view to the top of another view in a RelativeLayout in Android

Do you Know? How to Align top of one view to the top of another view in a RelativeLayout in Android

activity_main.xml

<RelativeLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/rl"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:padding="16dp"
    tools:context=".MainActivity"
    android:background="@android:color/white"
    >
    <Button
        android:id="@+id/btn"
        android:layout_width="wrap_content"
        android:layout_height="150dp"
        android:text="First Button"
        android:layout_alignParentBottom="true"
        />
    <Button
        android:id="@+id/btn2"
        android:layout_width="wrap_content"
        android:layout_height="100dp"
        android:text="Second Button"
        android:layout_alignTop="@id/btn"
        android:layout_toRightOf="@id/btn"
        />
    <Button
        android:id="@+id/btn3"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Third Button"
        android:layout_alignTop="@id/btn2"
        android:layout_toRightOf="@id/btn2"
        />
</RelativeLayout>