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.

Input: Consider Input: mant air planes on a run way with a sky background

Output: mant


Input: Consider Input: two trains are parked side by side at the staiton

Output: staiton


Input: Consider Input: Two boys, one very young, and one a little older, ride skateboards in the stret.


Output: stret.