I have a list of Keyword ids: {1,2,3,4}

Keyword entity:

```
public class Keyword
{
    public int Id { get; set; }

    public virtual ICollection<Ad> Ads { get; set; }
}

```

And a list of Ads that have each a set of Keywords:

```
public class Ad
{
    public int Id { get; set; }

    public virtual ICollection<Keyword> Keywords { get; set; }
}

```

How can I get the Ad Id's that match ALL the list of Keyword ids ?

Thanks