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.

[Q]: Teenagers skateboard on the concrete outside a commercial buildoing.
[A]: buildoing.


[Q]: A resd double decker metro bus rounds the corner of a city street.
[A]: resd


[Q]: geee sit in water next to a small waterfall
[A]:
geee