Gromozeka has
n-1 integers written on cards and laid out in a row in random order. It computed a bitwise XOR (
xor) between all the numbers written. The calculated number (
X) he wrote down on a new card and added it to the end of all cards with numbers. Now he has n number cards. He shuffled all the cards and arranged them again in a row in random order.
Gromozeka showed you all the
n cards and asks you to guess the number
X that was written on the new card.
Input
The first line of the input contains an integer
n - the number of cards with numbers (2 <=
n <= 100
). The second line contains
n integers - the numbers written on the cards (each number belongs to the interval [0, 127]).
Imprint
Print the answer one integer - the number
X that was written on the new card.
It is guaranteed that the answer exists. If there are multiple answers, print the minimum
X.
Examples
| # |
Input |
Output |
| 1 |
4
4 3 2 5
| 2 |