instruction:
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.
question:
a kisd's room with very many playing toys
answer:
kisd's


question:
Two cars are stopped at a red light and transit buses are in the backround.
answer:
backround.


question:
The doubkedecker bus is stopped on the road for the benefit of the passengers.
answer:

doubkedecker