List of countries that border only one other country

Columns: Country | Neighbour | Border length ( km ) | Border length ( mi )
Papua New Guinea | Indonesia | 820 | 510 | Portugal | Spain | 1,214 | 754 | Qatar | Saudi Arabia | 60 | 37 | San Marino | Italy | 39 | 24 | South Korea | North Korea | 238 | 148 | Timor-Leste | Indonesia | 228 | 142 | United Kingdom | Ireland | 360 | 220 | Vatican City | Italy | 3.2 | 2.0

Example questions:
How many kilometres long is the border of the country on this list that was established by the Lateran Treaty in 1929 ? | How many miles long is the border of the country on the list of countries bordering only one country known as the Abode of Peace ? | The country on this list that borders only Germany lost territory to which country after wars that began in the 17th century ? | Which country only borders the country on this list with the capital city of Dublin ? | What country only borders the country on this list that also includes two autonomous territories in the North Atlantic Ocean ?

Answers:
3.2 | 237 | Sweden | United Kingdom | Germany