The given sentence contains a typo which could be one of the following four types: (1) swapped letters of a word e.g. 'niec' is a typo of the word 'nice'. (2) missing letter in a word e.g. 'nic' is a typo of the word 'nice'. (3) extra letter in a word e.g. 'nicce' is a typo of the word 'nice'. (4) replaced letter in a word e.g 'nicr' is a typo of the word 'nice'. You need to identify the typo in the given sentence. To do this, answer with the word containing the typo.

[EX Q]: A conputer monitor and keyboard sit on a desk.
[EX A]: conputer

[EX Q]: A coulpe of buses driving down a street next to tall buildings.
[EX A]: coulpe

[EX Q]: Doosr open to the train to let people board and unboard
[EX A]:
Doosr