Dynamics NAV sizing

Hello all

I need your advice about a sizing.

My customer needs to install one server to Russia.

There are 20 companies (10 in Russia and 10 in Cyprus) which are working with this server.

The daily transactions (sales orders, purchase orders, invoices are about 1000 per company).

Concurrent users 120.

Could you inform me about the sizing of this hardware?

Thnaks in advance.