DWITE Online Computer Programming Contest, October 2009, Problem 3
You have a continuous sequence of unique numbers, 
~1, 2, \dots, N~, that you like very much, but your little sister always steals one (and only one), and randomly re-arranges the rest in an attempt to hide the crime. Given 
~N-1~ numbers, in a random order, find out which number was taken.
The input will contain 5 sets of input. The first line will be an integer 
~1 \le M \le 100~, the number of items remaining. Followed by 
~M~ lines of unique integers, from at least 
~1~ to at most 
~M+1~.
The output will contain 5 lines, each an integer from the missing set.
Note: the original sorted sequence is 
~\{1, 2, \dots, N\}~. Any of the numbers (including ~1~ or 
~N~) can be taken.
Sample Input
2
1
2
2
2
3
2
1
3
Sample Output
3
1
2
Problem Resource: DWITE
Comments
The question states there will be 5 sets of input, but in the example there are only 3?