The islanders of Fictitia have a rather eccentric postal system. Postage for an item can be ANY whole number amount from 1 dinar to 26 dinari, and you MUST use exact postage.
Frustratingly, there is only space on the envelopes in Fictitia to attach a maximum of TWO stamps.
What is more, they only have SEVEN different denominations of stamps, can you work out what they are?