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.

Example Input: An eklderly woman celebrates her 90th birthday with a cake.
Example Output: eklderly

Example Input: There is an open store on the stret.
Example Output: stret.

Example Input: A group of girls on a yellow rowboqat.
Example Output:
rowboqat.