NPC selling houses. Buying by house name.

[Vanitas]

I tried to make NPC selling houses but I want that player will be saying name of house which he want to buy.
I just don't know how to "change" name of house to his ID.
I have table of houses and IDs:

    local houseName =
    {
        -- abdendriel
        ["Coastwood 1"] = 1,
        ["Coastwood 2"] = 2,
        ["Coastwood 3"] = 2,
        ["Coastwood 5"] = 4,
        ["Coastwood 5"] = 5,
        ["Coastwood 6"] = 6,
        ["Coastwood 7"] = 7,
        ["Coastwood 8"] = 8,
        ["Coastwood 9"] = 9,
        ["Coastwood 10"] = 10        
    }

But I have no idea how to use it in NPC becouse NPC is using

function onCreatureSay(cid, type, msg)

and to read table I need

function onSay(cid, words, param)

 

[Vanitas]

BUMP
It doesn't have to be like I've written.
The point is that I want to use names of houses, if someone have different idea post it