Laravel: Count rows with relationships tables

I have two tables who are related.

settlements:

| id | reon_id | name |

add_members:

| id | settlement_id | first_name | last_name | cipher_id |

In Settlement Model their related like this:

public function members()
{
    return $this->hasMany('App\AddMember');
}

So, first I need all members with reon_id of 1, so I did like this:

$members = Settlement::where('reon_id', '1')
  ->with('members')
  ->count();

and that works. But now, I need same thing but also with cipher_id of 1. If I add ->where('cipher_id', '1') after ->with('members') I get this error:

(2/2) QueryException SQLSTATE[42S22]: Column not found: 1054 Unknown column 'cipher_id' in 'where clause'

Where I am wrong?

via Chebli Mohamed