The Post Office issues inland letter cards for transmission via inland post for the public's usage. A "Letter card" is a piece of paper suitable for letter writing that has been folded and gummed. A letter card bears a stamp with the necessary postage value imprinted on it. In addition, some countries have postal codes which are printed on the edge of the card in small characters. Inland mail is mail that does not go by airmail to another country but instead travels by road or rail within the country itself. This type of mail includes letters, packages, and electronic messages such as email. In contrast, international mail consists of letters and packages that are sent by plane to other countries. It can also include electronic messages like email. Inland mail has its own system of carriers and offices separate from that of international mail. The United States Postal Service (USPS) operates over 700 postal facilities across the country to deliver mail for federal agencies as well as private businesses and individuals. These include post offices, bulk mail centers, packet stations, and postal counters at airports and train stations. Mail for federal agencies including Congress and their offices is delivered separately from regular first-class mail. Private companies delivery mail for a fee. These are called third-party mailers. They deliver letters, packages, and even magazines to remote areas where the USPS doesn't provide service.